tests: coverage round 8 (serialization, folder, text/polygon, probe, render tail)

- node_save_load_test: Node Save/Load round trips for values, keyframes,
  hints, caches, connections, positions
- node_polygon_folder_test: Folder child management, PolygonGenerator
  rasterization/gizmos, TextGeneratorV1/V2
- footage_probe_test: real FFmpeg/OIIO probing of demo.mp4/img.png,
  metadata cache, footage state transitions
- render_tail_test: DynamicRenderer, color-context shader plumbing,
  PreviewAutoCacher pause/clear paths, DiskManager edges,
  AudioPlaybackCache segment I/O

Also fixes AudioPlaybackCache::WritePartOfSampleBuffer, found by the new
tests: zero padding was written via QFile::write(const char*) which
treats the buffer as a NUL-terminated string, so no padding bytes were
ever written; the write length was also computed from the segment end
instead of the range end, making WriteSilence() spin forever on an
empty buffer

app/render/audioplaybackcache.cpp

@@ -99,7 +99,9 @@ bool AudioPlaybackCache::WritePartOfSampleBuffer(const SampleBuffer &samples,
 		int64_t segment_end = segment_start + kDefaultSegmentSizePerChannel;
 
 		int64_t offset_in_segment = current_cache_offset - segment_start;
-		int64_t write_len = segment_end - offset_in_segment;
+		// Never write past the end of the requested range
+		int64_t write_len = std::min(segment_end - current_cache_offset,
+									 end_cache_offset - current_cache_offset);
 		int64_t max_buffer_len = end_buffer_offset - current_buffer_offset;
 		int64_t zero_len = 0;
 
@@ -119,13 +121,17 @@ bool AudioPlaybackCache::WritePartOfSampleBuffer(const SampleBuffer &samples,
 			QFile f(filename);
 			if (f.open(QFile::ReadWrite)) {
 				f.seek(offset_in_segment);
-				f.write(reinterpret_cast<const char *>(samples.data(channel)) +
+				if (write_len > 0) {
-							current_buffer_offset,
+					f.write(reinterpret_cast<const char *>(samples.data(channel)) +
-						write_len);
+								current_buffer_offset,
+							write_len);
+				}
 
 				if (zero_len > 0) {
+					// NOTE: the length must be passed explicitly; write(const
+					// char*) would treat the zeros as an empty C string
 					QByteArray b(zero_len, 0);
-					f.write(b.constData());
+					f.write(b.constData(), b.size());
 				}
 
 				f.close();
@@ -134,7 +140,7 @@ bool AudioPlaybackCache::WritePartOfSampleBuffer(const SampleBuffer &samples,
 			}
 		}
 
-		current_cache_offset += write_len;
+		current_cache_offset += write_len + zero_len;
 		current_buffer_offset += write_len;
 	}
 

tests/gtest/CMakeLists.txt

@@ -75,6 +75,10 @@ add_executable(olive-gtest
   node_distort_test.cpp
   node_filter_keying_test.cpp
   node_math_transition_test.cpp
+  node_save_load_test.cpp
+  node_polygon_folder_test.cpp
+  footage_probe_test.cpp
+  render_tail_test.cpp
   timeline_marker_test.cpp
   undo_stack_test.cpp
   plugin_support_test.cpp

tests/gtest/footage_probe_test.cpp

@@ -0,0 +1,486 @@
+#include <gtest/gtest.h>
+
+#include <QApplication>
+#include <QDir>
+#include <QFile>
+#include <QFileInfo>
+#include <QMetaObject>
+#include <QStandardPaths>
+#include <QTemporaryDir>
+#include <QVariant>
+#include <QWidget>
+
+#include "codec/decoder.h"
+#include "common/filefunctions.h"
+#include "core.h"
+#include "node/color/colormanager/colormanager.h"
+#include "node/globals.h"
+#include "node/project.h"
+#include "node/project/footage/footage.h"
+#include "node/project/footage/footagedescription.h"
+#include "render/diskmanager.h"
+#include "render/job/footagejob.h"
+#include "render/loopmode.h"
+#include "render/texture.h"
+
+namespace
+{
+
+QString DemoVideoPath()
+{
+	return QDir(QStringLiteral(OAK_TEST_SOURCE_DIR))
+		.filePath(QStringLiteral("tests/demo.mp4"));
+}
+
+QString TestImagePath()
+{
+	return QDir(QStringLiteral(OAK_TEST_SOURCE_DIR))
+		.filePath(QStringLiteral("tests/img.png"));
+}
+
+// Mirrors the cache path expression used by Footage::Reprobe()
+QString MetadataCacheFileFor(const QString &media_path)
+{
+	return QDir(QStandardPaths::writableLocation(QStandardPaths::CacheLocation))
+		.filePath(olive::FileFunctions::GetUniqueFileIdentifier(media_path));
+}
+
+} // namespace
+
+TEST(FootageProbe, FFmpegProbeOfDemoMp4ReportsExpectedStreams)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::DecoderPtr decoder =
+		olive::Decoder::CreateFromID(QStringLiteral("ffmpeg"));
+	ASSERT_TRUE(decoder);
+
+	const olive::FootageDescription desc = decoder->Probe(path, nullptr);
+	ASSERT_TRUE(desc.IsValid());
+	EXPECT_EQ(desc.decoder(), QStringLiteral("ffmpeg"));
+
+	// The file holds video + audio + a timecode data track. The data track is
+	// counted in the total but not exposed as a usable stream.
+	ASSERT_EQ(desc.GetVideoStreams().size(), 1);
+	ASSERT_EQ(desc.GetAudioStreams().size(), 1);
+	EXPECT_EQ(desc.GetSubtitleStreams().size(), 0);
+	EXPECT_EQ(desc.GetStreamCount(), 3);
+
+	const olive::VideoParams &video = desc.GetVideoStreams().first();
+	EXPECT_EQ(video.stream_index(), 0);
+	EXPECT_EQ(video.width(), 1920);
+	EXPECT_EQ(video.height(), 1080);
+	EXPECT_EQ(video.video_type(), olive::VideoParams::kVideoTypeVideo);
+	EXPECT_EQ(video.interlacing(), olive::VideoParams::kInterlaceNone);
+	EXPECT_EQ(video.pixel_aspect_ratio(), olive::rational(1, 1));
+	EXPECT_EQ(video.frame_rate(), olive::rational(25));
+	EXPECT_EQ(video.time_base(), olive::rational(1, 12800));
+	EXPECT_EQ(video.duration(), 217600); // 17 seconds at 1/12800
+	EXPECT_NE(video.format(), olive::core::PixelFormat::INVALID);
+	EXPECT_GT(video.channel_count(), 0);
+
+	const olive::core::AudioParams &audio = desc.GetAudioStreams().first();
+	EXPECT_EQ(audio.stream_index(), 1);
+	EXPECT_EQ(audio.sample_rate(), 48000);
+	EXPECT_EQ(audio.channel_count(), 2);
+	EXPECT_EQ(audio.time_base(), olive::rational(1, 48000));
+	EXPECT_EQ(audio.duration(), 816000); // 17 seconds at 1/48000
+
+	// The file's timecode track starts at 01:00:00:00
+	ASSERT_TRUE(desc.HasSourceStartTime());
+	EXPECT_EQ(desc.source_start_time(), olive::rational(3600));
+	EXPECT_EQ(desc.source_start_time_source(), QStringLiteral("timecode"));
+}
+
+TEST(FootageProbe, ProbeOfUnprobeableFileYieldsInvalidDescription)
+{
+	QTemporaryDir dir;
+	ASSERT_TRUE(dir.isValid());
+
+	const QString path =
+		QDir(dir.path()).filePath(QStringLiteral("not_media.txt"));
+	{
+		QFile file(path);
+		ASSERT_TRUE(file.open(QFile::WriteOnly));
+		file.write("this is not a media file");
+	}
+
+	for (const olive::DecoderPtr &decoder :
+		 olive::Decoder::ReceiveListOfAllDecoders()) {
+		EXPECT_FALSE(decoder->Probe(path, nullptr).IsValid())
+			<< decoder->id().toStdString();
+	}
+}
+
+class FootageProbeTest : public ::testing::Test {
+protected:
+	void SetUp() override
+	{
+		if (!olive::Core::instance()) {
+			// Leaked intentionally: Core is process-wide (matches footage_test)
+			new olive::Core(olive::Core::CoreParams());
+		}
+
+		// Footage::Value() resolves Project::cache_path(), which goes through
+		// the DiskManager singleton
+		created_disk_manager_ = (olive::DiskManager::instance() == nullptr);
+		if (created_disk_manager_) {
+			olive::DiskManager::CreateInstance();
+		}
+
+		// Sandbox the footage metadata cache so real probes write into the
+		// temp dir instead of the user's cache
+		old_cache_home_ = qgetenv("XDG_CACHE_HOME");
+		had_cache_home_ = qEnvironmentVariableIsSet("XDG_CACHE_HOME");
+		qputenv("XDG_CACHE_HOME",
+				QDir(temp_dir_.path()).filePath(QStringLiteral("xdg")).toUtf8());
+		QDir().mkpath(
+			QStandardPaths::writableLocation(QStandardPaths::CacheLocation));
+
+		olive::ColorManager::SetUpDefaultConfig();
+
+		project_ = std::make_unique<olive::Project>();
+		project_->Initialize();
+	}
+
+	void TearDown() override
+	{
+		project_.reset();
+		if (created_disk_manager_) {
+			olive::DiskManager::DestroyInstance();
+		}
+		if (had_cache_home_) {
+			qputenv("XDG_CACHE_HOME", old_cache_home_);
+		} else {
+			qunsetenv("XDG_CACHE_HOME");
+		}
+	}
+
+	// Constructs a Footage pointing at path; the constructor's set_filename()
+	// call probes the file synchronously before the node joins the graph
+	olive::Footage *AddProbedFootage(const QString &path)
+	{
+		auto *footage = new olive::Footage(path);
+		footage->setParent(project_.get());
+		return footage;
+	}
+
+	QTemporaryDir temp_dir_;
+	QByteArray old_cache_home_;
+	bool had_cache_home_ = false;
+	bool created_disk_manager_ = false;
+	std::unique_ptr<olive::Project> project_;
+};
+
+TEST_F(FootageProbeTest, ProbingDemoMp4PopulatesFootageState)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *footage = AddProbedFootage(path);
+
+	EXPECT_TRUE(footage->IsValid());
+	EXPECT_EQ(footage->decoder(), QStringLiteral("ffmpeg"));
+	EXPECT_EQ(footage->timestamp(),
+			  QFileInfo(path).lastModified().toMSecsSinceEpoch());
+
+	// Video + audio streams are usable; the timecode data track only shows up
+	// in the total stream count
+	EXPECT_EQ(footage->GetTotalStreamCount(), 3);
+	EXPECT_EQ(footage->GetVideoStreamCount(), 1);
+	EXPECT_EQ(footage->GetAudioStreamCount(), 1);
+	EXPECT_EQ(footage->GetSubtitleStreamCount(), 0);
+
+	EXPECT_EQ(footage->GetStreamIndex(olive::Track::kVideo, 0), 0);
+	EXPECT_EQ(footage->GetStreamIndex(olive::Track::kAudio, 0), 1);
+	EXPECT_EQ(footage->GetReferenceFromRealIndex(0),
+			  olive::Track::Reference(olive::Track::kVideo, 0));
+	EXPECT_EQ(footage->GetReferenceFromRealIndex(1),
+			  olive::Track::Reference(olive::Track::kAudio, 0));
+	EXPECT_EQ(footage->GetReferenceFromRealIndex(2).type(),
+			  olive::Track::kNone);
+
+	EXPECT_EQ(footage->GetConnectedTextureOutput(),
+			  static_cast<olive::Node *>(footage));
+	EXPECT_EQ(footage->GetConnectedSampleOutput(),
+			  static_cast<olive::Node *>(footage));
+
+	const olive::VideoParams video = footage->GetVideoParams(0);
+	ASSERT_TRUE(video.is_valid());
+	EXPECT_EQ(video.stream_index(), 0);
+	EXPECT_EQ(video.width(), 1920);
+	EXPECT_EQ(video.height(), 1080);
+	EXPECT_EQ(video.video_type(), olive::VideoParams::kVideoTypeVideo);
+	EXPECT_EQ(video.frame_rate(), olive::rational(25));
+	EXPECT_EQ(video.time_base(), olive::rational(1, 12800));
+	EXPECT_EQ(video.duration(), 217600);
+	EXPECT_EQ(video.color_range(), olive::VideoParams::kColorRangeLimited);
+	EXPECT_TRUE(video.enabled());
+	// The FFmpeg probe leaves colorspace unset so the project default applies
+	EXPECT_TRUE(video.colorspace().isEmpty());
+
+	const olive::core::AudioParams audio = footage->GetAudioParams(0);
+	ASSERT_TRUE(audio.is_valid());
+	EXPECT_EQ(audio.stream_index(), 1);
+	EXPECT_EQ(audio.sample_rate(), 48000);
+	EXPECT_EQ(audio.channel_count(), 2);
+	EXPECT_EQ(audio.duration(), 816000);
+	EXPECT_TRUE(audio.enabled());
+}
+
+TEST_F(FootageProbeTest, ProbingDemoMp4SetsLengthsAndSourceStartTime)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *footage = AddProbedFootage(path);
+	footage->VerifyLength();
+
+	// Both streams describe 17 seconds of media
+	EXPECT_EQ(footage->GetVideoLength(), olive::rational(17));
+	EXPECT_EQ(footage->GetAudioLength(), olive::rational(17));
+	EXPECT_EQ(footage->GetLength(), olive::rational(17));
+
+	// The embedded 01:00:00:00 timecode becomes the source start time
+	ASSERT_TRUE(footage->HasSourceStartTime());
+	EXPECT_EQ(footage->source_start_time(), olive::rational(3600));
+	EXPECT_EQ(footage->source_start_time_source(), QStringLiteral("timecode"));
+}
+
+TEST_F(FootageProbeTest, ProbingPngImageProducesSingleStillStream)
+{
+	const QString path = TestImagePath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *footage = AddProbedFootage(path);
+
+	EXPECT_TRUE(footage->IsValid());
+	// Still images are handled by the OIIO decoder, which probes before FFmpeg
+	EXPECT_EQ(footage->decoder(), QStringLiteral("oiio"));
+
+	EXPECT_EQ(footage->GetTotalStreamCount(), 1);
+	EXPECT_EQ(footage->GetVideoStreamCount(), 1);
+	EXPECT_EQ(footage->GetAudioStreamCount(), 0);
+	EXPECT_EQ(footage->GetSubtitleStreamCount(), 0);
+
+	const olive::VideoParams still = footage->GetVideoParams(0);
+	ASSERT_TRUE(still.is_valid());
+	EXPECT_EQ(still.stream_index(), 0);
+	EXPECT_EQ(still.width(), 1920);
+	EXPECT_EQ(still.height(), 1080);
+	EXPECT_EQ(still.video_type(), olive::VideoParams::kVideoTypeStill);
+	EXPECT_EQ(still.channel_count(), 4);
+	EXPECT_EQ(still.format(), olive::core::PixelFormat::U8);
+	EXPECT_TRUE(still.premultiplied_alpha());
+	EXPECT_TRUE(still.enabled());
+	EXPECT_TRUE(still.colorspace().isEmpty());
+
+	// Stills have no duration and no source start time
+	footage->VerifyLength();
+	EXPECT_EQ(footage->GetVideoLength(), olive::rational(0));
+	EXPECT_EQ(footage->GetLength(), olive::rational(0));
+	EXPECT_FALSE(footage->HasSourceStartTime());
+
+	EXPECT_EQ(footage->GetConnectedTextureOutput(),
+			  static_cast<olive::Node *>(footage));
+	EXPECT_EQ(footage->GetConnectedSampleOutput(), nullptr);
+}
+
+TEST_F(FootageProbeTest, ProbedFootageValuePushesRealStreamJobs)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *footage = AddProbedFootage(path);
+	footage->VerifyLength();
+
+	// The colorspace fallback reads the project default, and the audio cache
+	// path comes from the project's cache settings
+	project_->SetDefaultInputColorSpace(QStringLiteral("ProbeInputSpace"));
+	project_->SetCacheLocationSetting(olive::Project::kCacheCustomPath);
+	const QString cache_path =
+		QDir(temp_dir_.path()).filePath(QStringLiteral("cache"));
+	project_->SetCustomCachePath(cache_path);
+
+	olive::NodeValueRow row;
+	row.insert(olive::Footage::kFilenameInput,
+			   olive::NodeValue(olive::NodeValue::kFile, path));
+
+	olive::VideoParams vparams(64, 64, olive::rational(1, 24),
+							   olive::core::PixelFormat::U8, 4);
+	const olive::NodeGlobals globals(vparams, olive::core::AudioParams(),
+									 olive::rational(0),
+									 olive::LoopMode::kLoopModeOff);
+
+	olive::NodeValueTable table;
+	footage->Value(row, globals, &table);
+
+	// Length, one texture job for the video stream, one sample job for the
+	// audio stream; the timecode data track produces no job
+	ASSERT_EQ(table.Count(), 3);
+
+	const olive::NodeValue length =
+		table.Get(olive::NodeValue::kRational, QStringLiteral("length"));
+	ASSERT_EQ(length.type(), olive::NodeValue::kRational);
+	EXPECT_EQ(length.toRational(), olive::rational(17));
+
+	const olive::TexturePtr texture =
+		table.Get(olive::NodeValue::kTexture, QStringLiteral("v:0"))
+			.toTexture();
+	ASSERT_NE(texture, nullptr);
+	EXPECT_EQ(texture->params().width(), 1920);
+	EXPECT_EQ(texture->params().height(), 1080);
+	// The probed stream has no colorspace, so the project default is used
+	EXPECT_EQ(texture->params().colorspace(),
+			  QStringLiteral("ProbeInputSpace"));
+
+	const auto *video_job =
+		static_cast<const olive::FootageJob *>(texture->job());
+	ASSERT_NE(video_job, nullptr);
+	EXPECT_EQ(video_job->decoder(), QStringLiteral("ffmpeg"));
+	EXPECT_EQ(video_job->filename(), path);
+	EXPECT_EQ(video_job->type(), olive::Track::kVideo);
+	EXPECT_EQ(video_job->length(), olive::rational(17));
+
+	const olive::FootageJob audio_job =
+		table.Get(olive::NodeValue::kSamples, QStringLiteral("a:0"))
+			.data()
+			.value<olive::FootageJob>();
+	EXPECT_EQ(audio_job.decoder(), QStringLiteral("ffmpeg"));
+	EXPECT_EQ(audio_job.filename(), path);
+	EXPECT_EQ(audio_job.type(), olive::Track::kAudio);
+	EXPECT_EQ(audio_job.audio_params().sample_rate(), 48000);
+	EXPECT_EQ(audio_job.length(), olive::rational(17));
+	EXPECT_EQ(audio_job.cache_path(), cache_path);
+}
+
+TEST_F(FootageProbeTest, SecondProbeReadsBackMetadataCache)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *first = AddProbedFootage(path);
+	ASSERT_TRUE(first->IsValid());
+
+	// The first probe writes a stream metadata cache into the cache location
+	const QString cache_file = MetadataCacheFileFor(path);
+	ASSERT_TRUE(QFileInfo::exists(cache_file));
+
+	// A second footage for the same file loads its metadata from that cache
+	// and ends up with identical state
+	olive::Footage *second = AddProbedFootage(path);
+	ASSERT_TRUE(second->IsValid());
+	EXPECT_EQ(second->decoder(), first->decoder());
+	EXPECT_EQ(second->GetTotalStreamCount(), first->GetTotalStreamCount());
+	EXPECT_EQ(second->GetVideoStreamCount(), first->GetVideoStreamCount());
+	EXPECT_EQ(second->GetAudioStreamCount(), first->GetAudioStreamCount());
+
+	const olive::VideoParams from_cache = second->GetVideoParams(0);
+	const olive::VideoParams probed = first->GetVideoParams(0);
+	EXPECT_EQ(from_cache.stream_index(), probed.stream_index());
+	EXPECT_EQ(from_cache.width(), probed.width());
+	EXPECT_EQ(from_cache.height(), probed.height());
+	EXPECT_EQ(from_cache.frame_rate(), probed.frame_rate());
+	EXPECT_EQ(from_cache.time_base(), probed.time_base());
+	EXPECT_EQ(from_cache.duration(), probed.duration());
+	EXPECT_EQ(from_cache.video_type(), probed.video_type());
+
+	ASSERT_TRUE(second->HasSourceStartTime());
+	EXPECT_EQ(second->source_start_time(), olive::rational(3600));
+	EXPECT_EQ(second->source_start_time_source(), QStringLiteral("timecode"));
+}
+
+TEST_F(FootageProbeTest, FilenameChangeToMissingFileClearsProbeState)
+{
+	const QString path = DemoVideoPath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	olive::Footage *footage = AddProbedFootage(path);
+	ASSERT_TRUE(footage->IsValid());
+	ASSERT_GT(footage->GetTotalStreamCount(), 0);
+
+	// Pointing the footage at a nonexistent file clears the probed state and
+	// the re-probe fails
+	footage->set_filename(
+		QDir(temp_dir_.path()).filePath(QStringLiteral("gone.mp4")));
+
+	EXPECT_FALSE(footage->IsValid());
+	EXPECT_EQ(footage->GetTotalStreamCount(), 0);
+	EXPECT_EQ(footage->GetVideoStreamCount(), 0);
+	EXPECT_EQ(footage->GetAudioStreamCount(), 0);
+	EXPECT_TRUE(footage->decoder().isEmpty());
+	EXPECT_EQ(footage->timestamp(), 0);
+	EXPECT_FALSE(footage->HasSourceStartTime());
+}
+
+TEST_F(FootageProbeTest, CheckFootageOnlyRespondsWithActiveWindow)
+{
+	const QString path = TestImagePath();
+	ASSERT_TRUE(QFileInfo::exists(path));
+
+	// Work on a copy so the original test asset is untouched
+	const QString copy =
+		QDir(temp_dir_.path()).filePath(QStringLiteral("image.png"));
+	ASSERT_TRUE(QFile::copy(path, copy));
+
+	olive::Footage *footage = AddProbedFootage(copy);
+	ASSERT_TRUE(footage->IsValid());
+	const qint64 probed_timestamp = footage->timestamp();
+	ASSERT_GT(probed_timestamp, 0);
+
+	// The file vanishes behind the footage's back
+	ASSERT_TRUE(QFile::remove(copy));
+
+	// Without an active window, CheckFootage is a no-op
+	ASSERT_TRUE(
+		QMetaObject::invokeMethod(footage, "CheckFootage", Qt::DirectConnection));
+	EXPECT_EQ(footage->timestamp(), probed_timestamp);
+	EXPECT_TRUE(footage->IsValid());
+
+	// With an active window, CheckFootage notices the missing file and
+	// re-probes. The re-probe resets the timestamp but, because Reprobe()
+	// never clears existing state for a missing file, the (now stale) probe
+	// data is kept until the filename itself changes.
+	{
+		QWidget window;
+		window.show();
+		window.activateWindow();
+		QCoreApplication::processEvents();
+		ASSERT_EQ(qApp->activeWindow(), &window);
+
+		ASSERT_TRUE(QMetaObject::invokeMethod(footage, "CheckFootage",
+											  Qt::DirectConnection));
+	}
+	ASSERT_EQ(qApp->activeWindow(), nullptr);
+
+	EXPECT_EQ(footage->timestamp(), 0);
+	EXPECT_TRUE(footage->IsValid());
+	EXPECT_EQ(footage->GetVideoStreamCount(), 1);
+}
+
+TEST_F(FootageProbeTest, ProbingExistingButInvalidMediaStaysInvalid)
+{
+	const QString path =
+		QDir(temp_dir_.path()).filePath(QStringLiteral("fake.mkv"));
+	{
+		QFile file(path);
+		ASSERT_TRUE(file.open(QFile::WriteOnly));
+		file.write("OAK_FAKE_MEDIA");
+	}
+
+	olive::Footage *footage = AddProbedFootage(path);
+
+	// The file exists but no decoder can probe it, so the footage stays
+	// invalid
+	EXPECT_FALSE(footage->IsValid());
+	EXPECT_TRUE(footage->decoder().isEmpty());
+	EXPECT_EQ(footage->GetTotalStreamCount(), 0);
+	EXPECT_EQ(footage->GetVideoStreamCount(), 0);
+	EXPECT_EQ(footage->GetAudioStreamCount(), 0);
+	EXPECT_EQ(footage->GetSubtitleStreamCount(), 0);
+
+	// Note: Reprobe caches even this failed probe result, so future reprobes
+	// of the same path reload the invalid description instead of re-probing
+	EXPECT_TRUE(QFileInfo::exists(MetadataCacheFileFor(path)));
+}

tests/gtest/node_save_load_test.cpp

@@ -0,0 +1,619 @@
+#include <gtest/gtest.h>
+
+#include <memory>
+
+#include <QPointF>
+#include <QString>
+#include <QUuid>
+#include <QVector>
+#include <QXmlStreamReader>
+#include <QXmlStreamWriter>
+
+#include "common/xmlutils.h"
+#include "core.h"
+#include "node/color/colormanager/colormanager.h"
+#include "node/factory.h"
+#include "node/generator/solid/solid.h"
+#include "node/generator/text/textv3.h"
+#include "node/keyframe.h"
+#include "node/math/math/math.h"
+#include "node/node.h"
+#include "node/project.h"
+#include "node/project/folder/folder.h"
+#include "node/serializeddata.h"
+#include "node/splitvalue.h"
+#include "render/diskmanager.h"
+
+namespace
+{
+
+// Serializes a single node into a standalone XML document, mirroring how
+// Project::Save wraps Node::Save in a "node" element
+QString SaveNodeXml(const olive::Node *node)
+{
+	QString xml;
+	QXmlStreamWriter writer(&xml);
+	writer.writeStartDocument();
+	writer.writeStartElement(QStringLiteral("node"));
+	node->Save(&writer);
+	writer.writeEndElement(); // node
+	writer.writeEndDocument();
+	return xml;
+}
+
+// Loads a document produced by SaveNodeXml into an existing node
+bool LoadNodeXml(olive::Node *node, const QString &xml,
+				 olive::SerializedData *data)
+{
+	QXmlStreamReader reader(xml);
+	if (!reader.readNextStartElement()) {
+		return false;
+	}
+	if (reader.name() != QStringLiteral("node")) {
+		return false;
+	}
+	return node->Load(&reader, data);
+}
+
+olive::Node *FindNodeById(olive::Project *project, const QString &id)
+{
+	for (olive::Node *n : project->nodes()) {
+		if (n->id() == id) {
+			return n;
+		}
+	}
+	return nullptr;
+}
+
+// Node that round-trips a custom payload through SaveCustom/LoadCustom and
+// records LoadFinishedEvent
+class CustomDataNode : public olive::Node {
+public:
+	CustomDataNode()
+	{
+		AddInput(QStringLiteral("Value"), olive::NodeValue::kFloat);
+	}
+
+	NODE_DEFAULT_FUNCTIONS(CustomDataNode)
+
+	virtual QString Name() const override
+	{
+		return QStringLiteral("CustomDataNode");
+	}
+
+	virtual QString id() const override
+	{
+		return QStringLiteral("org.oak.test.customdatanode");
+	}
+
+	virtual QVector<CategoryID> Category() const override
+	{
+		return { kCategoryUnknown };
+	}
+
+	virtual QString Description() const override
+	{
+		return QStringLiteral("Node with custom serialized data");
+	}
+
+	void Value(const olive::NodeValueRow &, const olive::NodeGlobals &,
+			   olive::NodeValueTable *) const override
+	{
+	}
+
+	virtual void SaveCustom(QXmlStreamWriter *writer) const override
+	{
+		writer->writeTextElement(QStringLiteral("greeting"), greeting_);
+	}
+
+	virtual bool LoadCustom(QXmlStreamReader *reader,
+							olive::SerializedData *data) override
+	{
+		Q_UNUSED(data)
+
+		while (olive::XMLReadNextStartElement(reader)) {
+			if (reader->name() == QStringLiteral("greeting")) {
+				greeting_ = reader->readElementText();
+			} else if (reader->name() == QStringLiteral("explode")) {
+				reader->skipCurrentElement();
+				return false;
+			} else {
+				reader->skipCurrentElement();
+			}
+		}
+
+		return true;
+	}
+
+	virtual void LoadFinishedEvent() override
+	{
+		load_finished_called_ = true;
+	}
+
+	QString greeting_;
+	bool load_finished_called_ = false;
+};
+
+} // namespace
+
+class NodeSaveLoadTest : public ::testing::Test {
+protected:
+	void SetUp() override
+	{
+		olive::ColorManager::SetUpDefaultConfig();
+
+		// Cache UUID changes resolve a cache path through the DiskManager
+		// singleton, which itself touches Core (same pattern as
+		// project_factory_test)
+		if (!olive::Core::instance()) {
+			new olive::Core(olive::Core::CoreParams()); // intentionally leaked
+		}
+		if (!olive::DiskManager::instance()) {
+			olive::DiskManager::CreateInstance();
+		}
+
+		project_ = std::make_unique<olive::Project>();
+		project_->Initialize();
+	}
+
+	template <typename T> T *AddNode()
+	{
+		T *node = new T();
+		node->setParent(project_.get());
+		return node;
+	}
+
+	std::unique_ptr<olive::Project> project_;
+};
+
+TEST_F(NodeSaveLoadTest, StandardValuesLabelAndColorRoundTrip)
+{
+	auto *src = AddNode<olive::MathNode>();
+	src->SetLabel(QStringLiteral("Labeled"));
+	src->SetOverrideColor(3);
+	src->SetStandardValue(olive::MathNode::kParamAIn, 3.5);
+	src->SetStandardValue(olive::MathNode::kParamBIn, -2.25);
+	src->SetOperation(olive::MathNode::kOpMultiply);
+
+	const QString xml = SaveNodeXml(src);
+	EXPECT_TRUE(xml.contains(QStringLiteral("version=\"1\"")));
+	EXPECT_TRUE(xml.contains(
+		QStringLiteral("id=\"org.olivevideoeditor.Olive.math\"")));
+
+	olive::MathNode loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	EXPECT_EQ(loaded.GetLabel(), QStringLiteral("Labeled"));
+	EXPECT_EQ(loaded.GetOverrideColor(), 3);
+	EXPECT_DOUBLE_EQ(
+		loaded.GetStandardValue(olive::MathNode::kParamAIn).toDouble(), 3.5);
+	EXPECT_DOUBLE_EQ(
+		loaded.GetStandardValue(olive::MathNode::kParamBIn).toDouble(), -2.25);
+	EXPECT_EQ(int(loaded.GetOperation()), int(olive::MathNode::kOpMultiply));
+
+	// The "ptr" attribute maps the serialized address to the loaded instance
+	EXPECT_EQ(data.node_ptrs.value(reinterpret_cast<quintptr>(src)), &loaded);
+
+	// A non-keyframable input never reports keyframing after load
+	EXPECT_FALSE(loaded.IsInputKeyframing(olive::MathNode::kMethodIn));
+}
+
+TEST_F(NodeSaveLoadTest, ArrayElementsAndPerElementKeyframingRoundTrip)
+{
+	auto *src = AddNode<olive::TextGeneratorV3>();
+	src->InputArrayResize(olive::TextGeneratorV3::kArgsInput, 2);
+	src->SetStandardValue(
+		olive::NodeInput(src, olive::TextGeneratorV3::kArgsInput, 0),
+		QStringLiteral("first"));
+	src->SetStandardValue(
+		olive::NodeInput(src, olive::TextGeneratorV3::kArgsInput, 1),
+		QStringLiteral("second"));
+
+	// Only element 1 is keyframed
+	src->SetInputIsKeyframing(olive::TextGeneratorV3::kArgsInput, true, 1);
+	auto *key = new olive::NodeKeyframe(
+		olive::rational(2), QStringLiteral("keyed"), olive::NodeKeyframe::kLinear,
+		0, 1, olive::TextGeneratorV3::kArgsInput);
+	key->setParent(src);
+
+	const QString xml = SaveNodeXml(src);
+
+	olive::TextGeneratorV3 loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	// The subelement count attribute resized the array on load
+	ASSERT_EQ(loaded.InputArraySize(olive::TextGeneratorV3::kArgsInput), 2);
+	EXPECT_EQ(loaded.GetSplitStandardValue(olive::TextGeneratorV3::kArgsInput, 0)
+				  .at(0)
+				  .toString(),
+			  QStringLiteral("first"));
+	EXPECT_EQ(loaded.GetSplitStandardValue(olive::TextGeneratorV3::kArgsInput, 1)
+				  .at(0)
+				  .toString(),
+			  QStringLiteral("second"));
+
+	EXPECT_FALSE(
+		loaded.IsInputKeyframing(olive::TextGeneratorV3::kArgsInput, 0));
+	EXPECT_TRUE(loaded.IsInputKeyframing(olive::TextGeneratorV3::kArgsInput, 1));
+
+	const QVector<olive::NodeKeyframeTrack> &tracks =
+		loaded.GetKeyframeTracks(olive::TextGeneratorV3::kArgsInput, 1);
+	ASSERT_EQ(tracks.at(0).size(), 1);
+	EXPECT_EQ(tracks.at(0).first()->time(), olive::rational(2));
+	EXPECT_EQ(tracks.at(0).first()->value().toString(),
+			  QStringLiteral("keyed"));
+	EXPECT_EQ(tracks.at(0).first()->element(), 1);
+}
+
+TEST_F(NodeSaveLoadTest, KeyframesAllTypesAndColorPropertiesRoundTrip)
+{
+	auto *src = AddNode<olive::SolidGenerator>();
+
+	olive::SplitValue color;
+	color.append(0.25);
+	color.append(0.5);
+	color.append(0.75);
+	color.append(1.0);
+	src->SetSplitStandardValue(olive::SolidGenerator::kColorInput, color, -1);
+
+	src->SetInputIsKeyframing(olive::SolidGenerator::kColorInput, true);
+
+	auto *linear = new olive::NodeKeyframe(
+		olive::rational(0), 0.0, olive::NodeKeyframe::kLinear, 0, -1,
+		olive::SolidGenerator::kColorInput);
+	linear->setParent(src);
+	auto *bezier = new olive::NodeKeyframe(
+		olive::rational(5), 1.0, olive::NodeKeyframe::kBezier, 0, -1,
+		olive::SolidGenerator::kColorInput);
+	bezier->setParent(src);
+	bezier->set_bezier_control_in(QPointF(0.25, -1.5));
+	bezier->set_bezier_control_out(QPointF(2.5, 0.75));
+	auto *hold = new olive::NodeKeyframe(
+		olive::rational(3), 0.5, olive::NodeKeyframe::kHold, 2, -1,
+		olive::SolidGenerator::kColorInput);
+	hold->setParent(src);
+
+	// Color inputs additionally serialize their color management properties
+	src->SetInputProperty(olive::SolidGenerator::kColorInput,
+						  QStringLiteral("col_input"), QStringLiteral("ACEScg"));
+	src->SetInputProperty(olive::SolidGenerator::kColorInput,
+						  QStringLiteral("col_display"), QStringLiteral("sRGB"));
+	src->SetInputProperty(olive::SolidGenerator::kColorInput,
+						  QStringLiteral("col_view"), QStringLiteral("Filmic"));
+	src->SetInputProperty(olive::SolidGenerator::kColorInput,
+						  QStringLiteral("col_look"), QStringLiteral("None"));
+
+	const QString xml = SaveNodeXml(src);
+
+	olive::SolidGenerator loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	EXPECT_TRUE(loaded.IsInputKeyframing(olive::SolidGenerator::kColorInput));
+
+	const QVector<olive::NodeKeyframeTrack> &tracks =
+		loaded.GetKeyframeTracks(olive::SolidGenerator::kColorInput, -1);
+	ASSERT_EQ(tracks.size(), 4);
+
+	// Track 0 holds the linear and bezier keys, sorted by time
+	ASSERT_EQ(tracks.at(0).size(), 2);
+	EXPECT_EQ(tracks.at(0).at(0)->time(), olive::rational(0));
+	EXPECT_EQ(tracks.at(0).at(0)->type(), olive::NodeKeyframe::kLinear);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(0)->value().toDouble(), 0.0);
+	EXPECT_EQ(tracks.at(0).at(1)->time(), olive::rational(5));
+	EXPECT_EQ(tracks.at(0).at(1)->type(), olive::NodeKeyframe::kBezier);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(1)->value().toDouble(), 1.0);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(1)->bezier_control_in().x(), 0.25);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(1)->bezier_control_in().y(), -1.5);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(1)->bezier_control_out().x(), 2.5);
+	EXPECT_DOUBLE_EQ(tracks.at(0).at(1)->bezier_control_out().y(), 0.75);
+
+	// Track 1 was left empty, track 2 holds the single hold key
+	EXPECT_TRUE(tracks.at(1).isEmpty());
+	ASSERT_EQ(tracks.at(2).size(), 1);
+	EXPECT_EQ(tracks.at(2).first()->time(), olive::rational(3));
+	EXPECT_EQ(tracks.at(2).first()->type(), olive::NodeKeyframe::kHold);
+	EXPECT_DOUBLE_EQ(tracks.at(2).first()->value().toDouble(), 0.5);
+	EXPECT_TRUE(tracks.at(3).isEmpty());
+
+	// The per-track standard values survive as well
+	const olive::SplitValue loaded_color =
+		loaded.GetSplitStandardValue(olive::SolidGenerator::kColorInput, -1);
+	ASSERT_EQ(loaded_color.size(), 4);
+	EXPECT_DOUBLE_EQ(loaded_color.at(0).toDouble(), 0.25);
+	EXPECT_DOUBLE_EQ(loaded_color.at(1).toDouble(), 0.5);
+	EXPECT_DOUBLE_EQ(loaded_color.at(2).toDouble(), 0.75);
+	EXPECT_DOUBLE_EQ(loaded_color.at(3).toDouble(), 1.0);
+
+	EXPECT_EQ(loaded.GetInputProperty(olive::SolidGenerator::kColorInput,
+									  QStringLiteral("col_input"))
+				  .toString(),
+			  QStringLiteral("ACEScg"));
+	EXPECT_EQ(loaded.GetInputProperty(olive::SolidGenerator::kColorInput,
+									  QStringLiteral("col_display"))
+				  .toString(),
+			  QStringLiteral("sRGB"));
+	EXPECT_EQ(loaded.GetInputProperty(olive::SolidGenerator::kColorInput,
+									  QStringLiteral("col_view"))
+				  .toString(),
+			  QStringLiteral("Filmic"));
+	EXPECT_EQ(loaded.GetInputProperty(olive::SolidGenerator::kColorInput,
+									  QStringLiteral("col_look"))
+				  .toString(),
+			  QStringLiteral("None"));
+}
+
+TEST_F(NodeSaveLoadTest, ValueHintsRoundTrip)
+{
+	auto *src = AddNode<olive::MathNode>();
+	src->SetValueHintForInput(
+		olive::MathNode::kParamAIn,
+		olive::Node::ValueHint(
+			{ olive::NodeValue::kVec2, olive::NodeValue::kTexture }, 3,
+			QStringLiteral("tag")));
+	src->SetValueHintForInput(olive::MathNode::kParamBIn,
+							  olive::Node::ValueHint(QStringLiteral("elem")), 2);
+
+	const QString xml = SaveNodeXml(src);
+
+	olive::MathNode loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	const olive::Node::ValueHint hint =
+		loaded.GetValueHintForInput(olive::MathNode::kParamAIn);
+	ASSERT_EQ(hint.types().size(), 2);
+	EXPECT_EQ(hint.types().at(0), olive::NodeValue::kVec2);
+	EXPECT_EQ(hint.types().at(1), olive::NodeValue::kTexture);
+	EXPECT_EQ(hint.index(), 3);
+	EXPECT_EQ(hint.tag(), QStringLiteral("tag"));
+
+	// Hints are tracked per element
+	EXPECT_EQ(loaded.GetValueHintForInput(olive::MathNode::kParamBIn, 2).tag(),
+			  QStringLiteral("elem"));
+	EXPECT_EQ(loaded.GetValueHintForInput(olive::MathNode::kParamBIn, 1).tag(),
+			  QString());
+	EXPECT_EQ(loaded.GetValueHints().size(), 2);
+}
+
+TEST_F(NodeSaveLoadTest, CacheUuidsRoundTrip)
+{
+	olive::MathNode src;
+
+	const QUuid audio_uuid(
+		QStringLiteral("{11111111-1111-1111-1111-111111111111}"));
+	const QUuid video_uuid(
+		QStringLiteral("{22222222-2222-2222-2222-222222222222}"));
+	const QUuid thumb_uuid(
+		QStringLiteral("{33333333-3333-3333-3333-333333333333}"));
+	const QUuid waveform_uuid(
+		QStringLiteral("{44444444-4444-4444-4444-444444444444}"));
+
+	src.audio_playback_cache()->SetUuid(audio_uuid);
+	src.video_frame_cache()->SetUuid(video_uuid);
+	src.thumbnail_cache()->SetUuid(thumb_uuid);
+	src.waveform_cache()->SetUuid(waveform_uuid);
+
+	const QString xml = SaveNodeXml(&src);
+
+	olive::MathNode loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	EXPECT_EQ(loaded.audio_playback_cache()->GetUuid(), audio_uuid);
+	EXPECT_EQ(loaded.video_frame_cache()->GetUuid(), video_uuid);
+	EXPECT_EQ(loaded.thumbnail_cache()->GetUuid(), thumb_uuid);
+	EXPECT_EQ(loaded.waveform_cache()->GetUuid(), waveform_uuid);
+}
+
+TEST_F(NodeSaveLoadTest, CustomDataAndLoadFinishedEventRoundTrip)
+{
+	CustomDataNode src;
+	src.greeting_ = QStringLiteral("hello custom");
+
+	const QString xml = SaveNodeXml(&src);
+	EXPECT_TRUE(xml.contains(QStringLiteral("hello custom")));
+
+	CustomDataNode loaded;
+	olive::SerializedData data;
+	ASSERT_TRUE(LoadNodeXml(&loaded, xml, &data));
+
+	EXPECT_EQ(loaded.greeting_, QStringLiteral("hello custom"));
+	EXPECT_TRUE(loaded.load_finished_called_);
+
+	// A LoadCustom failure propagates out of Node::Load
+	const QString fail_xml = QStringLiteral(
+		"<node><custom><explode/></custom></node>");
+	CustomDataNode failing;
+	olive::SerializedData fail_data;
+	QXmlStreamReader reader(fail_xml);
+	ASSERT_TRUE(reader.readNextStartElement());
+	ASSERT_EQ(reader.name(), QStringLiteral("node"));
+	EXPECT_FALSE(failing.Load(&reader, &fail_data));
+}
+
+TEST_F(NodeSaveLoadTest, UnknownElementsAndVersionAreSkipped)
+{
+	olive::MathNode node;
+
+	// Unknown elements are skipped at every level of the node format, and an
+	// unrecognized version attribute does not fail the load
+	const QString xml = QStringLiteral(
+		"<node version=\"999\" id=\"org.olivevideoeditor.Olive.math\">"
+		"<mystery><nested attr=\"1\"/></mystery>"
+		"<label>kept</label>"
+		"<links><strange/></links>"
+		"<connections>"
+		"<strange/>"
+		"<connection input=\"param_a_in\" element=\"-1\">"
+		"<weird/>"
+		"<output>12345</output>"
+		"</connection>"
+		"</connections>"
+		"<hints><strange/></hints>"
+		"<context><strange/></context>"
+		"<caches>"
+		"<mysterycache>{00000000-0000-0000-0000-000000000000}</mysterycache>"
+		"</caches>"
+		"<input id=\"param_a_in\"><oddstandard/></input>"
+		"</node>");
+
+	olive::SerializedData data;
+	QXmlStreamReader reader(xml);
+	ASSERT_TRUE(reader.readNextStartElement());
+	ASSERT_EQ(reader.name(), QStringLiteral("node"));
+	EXPECT_TRUE(node.Load(&reader, &data));
+
+	EXPECT_EQ(node.GetLabel(), QStringLiteral("kept"));
+
+	// The one well-formed connection was still recorded
+	ASSERT_EQ(data.desired_connections.size(), 1);
+	EXPECT_EQ(data.desired_connections.first().input.input(),
+			  olive::MathNode::kParamAIn);
+	EXPECT_EQ(data.desired_connections.first().input.element(), -1);
+	EXPECT_EQ(data.desired_connections.first().output_node, quintptr(12345));
+
+	// The malformed input left the default value untouched
+	EXPECT_DOUBLE_EQ(
+		node.GetStandardValue(olive::MathNode::kParamAIn).toDouble(), 0.0);
+}
+
+TEST_F(NodeSaveLoadTest, LoadInputWithMissingOrUnknownIdIsSkipped)
+{
+	olive::MathNode node;
+
+	// An input with no id and an input whose id does not exist on the node
+	// both make LoadInput fail internally, but Node::Load ignores that return
+	// value and carries on
+	const QString xml = QStringLiteral(
+		"<node>"
+		"<input><primary><standard><track>9</track></standard></primary></input>"
+		"<input id=\"no_such_input\">"
+		"<primary><standard><track>9</track></standard></primary>"
+		"</input>"
+		"</node>");
+
+	olive::SerializedData data;
+	QXmlStreamReader reader(xml);
+	ASSERT_TRUE(reader.readNextStartElement());
+	ASSERT_EQ(reader.name(), QStringLiteral("node"));
+	EXPECT_TRUE(node.Load(&reader, &data));
+
+	EXPECT_DOUBLE_EQ(
+		node.GetStandardValue(olive::MathNode::kParamAIn).toDouble(), 0.0);
+	EXPECT_DOUBLE_EQ(
+		node.GetStandardValue(olive::MathNode::kParamBIn).toDouble(), 0.0);
+}
+
+TEST_F(NodeSaveLoadTest, ConnectionsLinksAndPositionsResolveAfterProjectLoad)
+{
+	olive::NodeFactory::Initialize();
+
+	auto *src = AddNode<olive::SolidGenerator>();
+	auto *dst = AddNode<olive::MathNode>();
+	auto *text = AddNode<olive::TextGeneratorV3>();
+	text->InputArrayResize(olive::TextGeneratorV3::kArgsInput, 2);
+
+	olive::Node::ConnectEdge(
+		src, olive::NodeInput(dst, olive::MathNode::kParamAIn));
+	olive::Node::ConnectEdge(
+		dst, olive::NodeInput(text, olive::TextGeneratorV3::kArgsInput, 1));
+	olive::Node::Link(src, dst);
+
+	olive::Folder *root = project_->root();
+	root->SetNodePositionInContext(
+		src, olive::Node::Position(QPointF(10.0, 20.0), true));
+	root->SetNodePositionInContext(
+		dst, olive::Node::Position(QPointF(-3.5, 7.25), false));
+
+	QString xml;
+	QXmlStreamWriter writer(&xml);
+	writer.writeStartDocument();
+	writer.writeStartElement(QStringLiteral("project"));
+	project_->Save(&writer);
+	writer.writeEndElement(); // project
+	writer.writeEndDocument();
+
+	// The project being loaded into must not be Initialize()d: Load()
+	// re-resolves the root folder from the saved settings
+	olive::Project loaded;
+	olive::SerializedData data;
+	{
+		QXmlStreamReader reader(xml);
+		ASSERT_TRUE(reader.readNextStartElement());
+		ASSERT_EQ(reader.name(), QStringLiteral("project"));
+		data = loaded.Load(&reader);
+	}
+
+	// Root folder plus the three nodes created above
+	ASSERT_EQ(loaded.nodes().size(), 4);
+
+	olive::Node *loaded_src = FindNodeById(&loaded, src->id());
+	olive::Node *loaded_dst = FindNodeById(&loaded, dst->id());
+	olive::Node *loaded_text = FindNodeById(&loaded, text->id());
+	ASSERT_NE(loaded_src, nullptr);
+	ASSERT_NE(loaded_dst, nullptr);
+	ASSERT_NE(loaded_text, nullptr);
+
+	// Both edges were recorded against the serialized addresses, including
+	// the array element index on the text input
+	ASSERT_EQ(data.desired_connections.size(), 2);
+	bool found_math_edge = false;
+	bool found_text_edge = false;
+	for (const auto &sc : data.desired_connections) {
+		if (sc.input.node() == loaded_dst) {
+			EXPECT_EQ(sc.input.input(), olive::MathNode::kParamAIn);
+			EXPECT_EQ(sc.input.element(), -1);
+			EXPECT_EQ(sc.output_node, reinterpret_cast<quintptr>(src));
+			found_math_edge = true;
+		} else if (sc.input.node() == loaded_text) {
+			EXPECT_EQ(sc.input.input(), olive::TextGeneratorV3::kArgsInput);
+			EXPECT_EQ(sc.input.element(), 1);
+			EXPECT_EQ(sc.output_node, reinterpret_cast<quintptr>(dst));
+			found_text_edge = true;
+		}
+	}
+	EXPECT_TRUE(found_math_edge);
+	EXPECT_TRUE(found_text_edge);
+
+	// Both nodes wrote their side of the link
+	EXPECT_EQ(data.block_links.size(), 2);
+
+	// The root folder recorded positions for the two placed nodes
+	olive::Folder *loaded_root = loaded.root();
+	ASSERT_NE(loaded_root, nullptr);
+	EXPECT_EQ(data.positions.value(loaded_root).size(), 2);
+
+	// Resolve the deferred state the same way
+	// ProjectSerializer230220::PostConnect does
+	for (const auto &sc : data.desired_connections) {
+		if (olive::Node *out = data.node_ptrs.value(sc.output_node)) {
+			olive::Node::ConnectEdge(out, sc.input);
+		}
+	}
+	for (const auto &link : data.block_links) {
+		olive::Node::Link(link.block, data.node_ptrs.value(link.link));
+	}
+	for (olive::Node *n : loaded.nodes()) {
+		n->PostLoadEvent(&data);
+	}
+
+	EXPECT_EQ(loaded_dst->GetConnectedOutput(olive::MathNode::kParamAIn),
+			  loaded_src);
+	EXPECT_EQ(loaded_text->GetConnectedOutput(
+				  olive::TextGeneratorV3::kArgsInput, 1),
+			  loaded_dst);
+	EXPECT_TRUE(olive::Node::AreLinked(loaded_src, loaded_dst));
+	EXPECT_TRUE(olive::Node::AreLinked(loaded_dst, loaded_src));
+
+	EXPECT_EQ(loaded_root->GetNodePositionInContext(loaded_src),
+			  QPointF(10.0, 20.0));
+	EXPECT_TRUE(loaded_root->IsNodeExpandedInContext(loaded_src));
+	EXPECT_EQ(loaded_root->GetNodePositionInContext(loaded_dst),
+			  QPointF(-3.5, 7.25));
+	EXPECT_FALSE(loaded_root->IsNodeExpandedInContext(loaded_dst));
+
+	olive::NodeFactory::Destroy();
+}

tests/gtest/render_tail_test.cpp

@@ -0,0 +1,872 @@
+#include <gtest/gtest.h>
+
+#include <cstring>
+
+#include <QCoreApplication>
+#include <QDir>
+#include <QFile>
+#include <QFileInfo>
+#include <QList>
+#include <QSignalSpy>
+#include <QTemporaryDir>
+#include <QVariant>
+
+#include "codec/conformmanager.h"
+#include "config/config.h"
+#include "core.h"
+#include "node/color/colormanager/colormanager.h"
+#include "node/generator/solid/solid.h"
+#include "node/keying/chromakey/chromakey.h"
+#include "node/output/viewer/viewer.h"
+#include "node/project.h"
+#include "olive/core/render/audioparams.h"
+#include "olive/core/render/samplebuffer.h"
+#include "render/audioplaybackcache.h"
+#include "render/backend/dynamicrenderer.h"
+#include "render/colorprocessor.h"
+#include "render/diskmanager.h"
+#include "render/job/colortransformjob.h"
+#include "render/previewautocacher.h"
+#include "render/renderer.h"
+#include "render/rendermanager.h"
+#include "render/texture.h"
+#include "render/videoparams.h"
+
+namespace
+{
+
+// CPU-only olive::Renderer that records the shader code it is asked to compile
+// so Renderer::GetColorContext() shader generation can be verified without a
+// GL/Vulkan backend.
+class ShaderCaptureRenderer : public olive::Renderer {
+public:
+	ShaderCaptureRenderer()
+		: create_shader_count(0)
+		, create_texture_count(0)
+		, blit_count(0)
+	{
+	}
+
+	bool Init() override
+	{
+		return true;
+	}
+
+	void PostDestroy() override
+	{
+	}
+
+	void PostInit() override
+	{
+	}
+
+	void ClearDestination(olive::Texture *texture, double r, double g, double b,
+						  double a) override
+	{
+	}
+
+	QVariant CreateNativeShader(olive::ShaderCode code) override
+	{
+		create_shader_count++;
+		last_frag_code = code.frag_code();
+		last_vert_code = code.vert_code();
+		return QVariant(create_shader_count);
+	}
+
+	void DestroyNativeShader(QVariant shader) override
+	{
+	}
+
+	void UploadToTexture(const QVariant &handle, const olive::VideoParams &params,
+						 const void *data, int linesize) override
+	{
+	}
+
+	void DownloadFromTexture(const QVariant &handle,
+							 const olive::VideoParams &params, void *data,
+							 int linesize) override
+	{
+	}
+
+	void Flush() override
+	{
+	}
+
+	olive::Color GetPixelFromTexture(olive::Texture *texture,
+									 const QPointF &pt) override
+	{
+		return olive::Color();
+	}
+
+	int create_shader_count;
+	int create_texture_count;
+	int blit_count;
+	QString last_frag_code;
+	QString last_vert_code;
+
+protected:
+	void Blit(QVariant shader, olive::AcceleratedJob &job,
+			  olive::Texture *destination, olive::VideoParams destination_params,
+			  bool clear_destination) override
+	{
+		blit_count++;
+	}
+
+	QVariant CreateNativeTexture(int width, int height, int depth,
+								 olive::PixelFormat format, int channel_count,
+								 const void *data, int linesize) override
+	{
+		create_texture_count++;
+		return QVariant(create_texture_count);
+	}
+
+	void DestroyNativeTexture(QVariant texture) override
+	{
+	}
+
+	void DestroyInternal() override
+	{
+	}
+};
+
+olive::ColorProcessorPtr MakeIdentityProcessor()
+{
+	olive::ColorManager::SetUpDefaultConfig();
+
+	OCIO::MatrixTransformRcPtr transform = OCIO::MatrixTransform::Create();
+	transform->setDirection(OCIO::TRANSFORM_DIR_FORWARD);
+
+	return olive::ColorProcessor::Create(
+		olive::ColorManager::GetDefaultConfig()->getProcessor(transform));
+}
+
+bool WriteFile(const QString &path, qint64 size)
+{
+	QFile file(path);
+	if (!file.open(QFile::WriteOnly)) {
+		return false;
+	}
+	file.write(QByteArray(static_cast<int>(size), 'x'));
+	file.close();
+	return true;
+}
+
+bool ReadBytesAt(const QString &path, qint64 offset, qint64 len, QByteArray *out)
+{
+	QFile f(path);
+	if (!f.open(QFile::ReadOnly)) {
+		return false;
+	}
+	if (!f.seek(offset)) {
+		return false;
+	}
+	*out = f.read(len);
+	return out->size() == len;
+}
+
+float BytesToFloat(const QByteArray &bytes)
+{
+	float v;
+	memcpy(&v, bytes.constData(), sizeof(v));
+	return v;
+}
+
+// AudioPlaybackCache always stores audio in fixed-size segments of 10 MB per
+// channel (AudioPlaybackCache::kDefaultSegmentSizePerChannel).
+const qint64 kSegmentSize = 10 * 1024 * 1024;
+
+} // namespace
+
+// A DynamicRenderer constructed with an empty backend name must report no
+// backend type; the name is stored verbatim (only lowercased).
+TEST(DynamicRenderer, EmptyBackendNameHasNoBackendType)
+{
+	olive::DynamicRenderer renderer{ QString() };
+	EXPECT_TRUE(renderer.backend_name().isEmpty());
+	EXPECT_FALSE(renderer.IsOpenGL());
+	EXPECT_FALSE(renderer.IsVulkan());
+
+	// Without a loaded backend, context and info accessors stay at defaults
+	EXPECT_EQ(renderer.OpenGLContext(), nullptr);
+
+	OakRenderBackendInfo info = {};
+	EXPECT_FALSE(renderer.GetBackendInfo(&info));
+}
+
+// BackendFromString lowercases its input before comparing, so mixed-case
+// spellings of every backend must resolve correctly.
+TEST(RenderManagerBackendStrings, FromStringIsCaseInsensitive)
+{
+	EXPECT_EQ(olive::RenderManager::BackendFromString(QStringLiteral("VULKAN")),
+			  olive::RenderManager::kVulkan);
+	EXPECT_EQ(
+		olive::RenderManager::BackendFromString(QStringLiteral("MultiProcess")),
+		olive::RenderManager::kMultiProcess);
+	EXPECT_EQ(olive::RenderManager::BackendFromString(QStringLiteral("DUMMY")),
+			  olive::RenderManager::kDummy);
+
+	// Unknown and empty strings fall through to OpenGL
+	EXPECT_EQ(olive::RenderManager::BackendFromString(QString()),
+			  olive::RenderManager::kOpenGL);
+}
+
+// BackendToString has a default return after the switch for out-of-range enum
+// values, which must be the OpenGL string.
+TEST(RenderManagerBackendStrings, ToStringFallsBackToOpenGLForUnknownEnum)
+{
+	EXPECT_EQ(olive::RenderManager::BackendToString(
+				  static_cast<olive::RenderManager::Backend>(42)),
+			  QStringLiteral("opengl"));
+}
+
+// A ColorTransformJob with a custom OCIO function name must have that name
+// embedded in the shader generated by GetColorContext (it is passed to
+// GpuShaderDesc::setFunctionName).
+TEST(RendererColorContext, CustomFunctionNameIsCompiledIntoShader)
+{
+	ShaderCaptureRenderer renderer;
+
+	olive::ColorProcessorPtr processor = MakeIdentityProcessor();
+	ASSERT_TRUE(processor);
+
+	olive::ColorTransformJob job;
+	job.SetColorProcessor(processor);
+	job.SetFunctionName(QStringLiteral("MyCustomOcioFunc"));
+
+	const olive::VideoParams params(32, 32, olive::PixelFormat::U8,
+									olive::VideoParams::kRGBAChannelCount);
+	renderer.BlitColorManaged(job, params);
+
+	ASSERT_EQ(renderer.create_shader_count, 1);
+	EXPECT_TRUE(
+		renderer.last_frag_code.contains(QStringLiteral("MyCustomOcioFunc")));
+	EXPECT_EQ(renderer.blit_count, 1);
+
+	renderer.Destroy();
+}
+
+// When the job names a custom shader source node, GetColorContext must ask the
+// node for its shader code (with the OCIO stub) instead of using the built-in
+// colormanage stub. ChromaKeyNode wraps the stub in its chroma-key shader.
+TEST(RendererColorContext, CustomShaderSourceSuppliesFragmentCode)
+{
+	ShaderCaptureRenderer renderer;
+
+	olive::ColorProcessorPtr processor = MakeIdentityProcessor();
+	ASSERT_TRUE(processor);
+
+	olive::ChromaKeyNode key_node;
+
+	olive::ColorTransformJob job;
+	job.SetColorProcessor(processor);
+	job.SetNeedsCustomShader(&key_node);
+
+	const olive::VideoParams params(32, 32, olive::PixelFormat::U8,
+									olive::VideoParams::kRGBAChannelCount);
+	renderer.BlitColorManaged(job, params);
+
+	ASSERT_EQ(renderer.create_shader_count, 1);
+	// A uniform name unique to chromakey.frag proves the node's code was used
+	EXPECT_TRUE(renderer.last_frag_code.contains(QStringLiteral("color_key")));
+	EXPECT_EQ(renderer.blit_count, 1);
+
+	renderer.Destroy();
+}
+
+class RenderTailAutoCacherTest : public ::testing::Test {
+protected:
+	void SetUp() override
+	{
+		olive::ColorManager::SetUpDefaultConfig();
+
+		// Use the dummy render backend so PreviewAutoCacher can be exercised
+		// without initializing OpenGL/Vulkan in the unit-test process.
+		olive::Config::Current()[QStringLiteral("GraphicsBackend")] =
+			QStringLiteral("dummy");
+
+		olive::DiskManager::CreateInstance();
+		olive::ConformManager::CreateInstance();
+		olive::RenderManager::CreateInstance();
+
+		project_ = std::make_unique<olive::Project>();
+		project_->Initialize();
+	}
+
+	void TearDown() override
+	{
+		project_.reset();
+		olive::RenderManager::DestroyInstance();
+		olive::ConformManager::DestroyInstance();
+		olive::DiskManager::DestroyInstance();
+	}
+
+	olive::ViewerOutput *CreateViewerWithParams()
+	{
+		auto *viewer = new olive::ViewerOutput();
+		viewer->setParent(project_.get());
+		viewer->SetVideoParams(
+			olive::VideoParams(64, 64, olive::rational(1, 25),
+							   olive::PixelFormat::U8,
+							   olive::VideoParams::kRGBAChannelCount));
+		return viewer;
+	}
+
+	std::unique_ptr<olive::Project> project_;
+};
+
+// While renders are paused, a forced cache range must sit in the pending queue;
+// unpausing dispatches it and emits StopCacheProxyTasks once the (single frame)
+// range iterator is exhausted.
+TEST_F(RenderTailAutoCacherTest, PausedRendersDelayForcedCacheRange)
+{
+	olive::ViewerOutput *viewer = CreateViewerWithParams();
+
+	olive::PreviewAutoCacher cacher;
+	cacher.SetProject(project_.get());
+
+	QSignalSpy stop_spy(&cacher, &olive::PreviewAutoCacher::StopCacheProxyTasks);
+
+	cacher.SetRendersPaused(true);
+	cacher.ForceCacheRange(
+		viewer, olive::TimeRange(olive::rational(0), olive::rational(1, 25)));
+	EXPECT_EQ(stop_spy.count(), 0);
+
+	cacher.SetRendersPaused(false);
+	EXPECT_GE(stop_spy.count(), 1);
+
+	// Deliver the queued RenderTicketWatcher::Finished emissions so the
+	// completed watchers are reaped before teardown.
+	QCoreApplication::processEvents();
+
+	cacher.SetProject(nullptr);
+}
+
+// The thumbnail pause gates only the video-job half of TryRender, so a forced
+// cache range queued while thumbnails are paused must wait for the unpause.
+TEST_F(RenderTailAutoCacherTest, PausedThumbnailsDelayForcedCacheRange)
+{
+	olive::ViewerOutput *viewer = CreateViewerWithParams();
+
+	olive::PreviewAutoCacher cacher;
+	cacher.SetProject(project_.get());
+
+	QSignalSpy stop_spy(&cacher, &olive::PreviewAutoCacher::StopCacheProxyTasks);
+
+	cacher.SetThumbnailsPaused(true);
+	cacher.ForceCacheRange(
+		viewer, olive::TimeRange(olive::rational(0), olive::rational(1, 25)));
+	EXPECT_EQ(stop_spy.count(), 0);
+
+	cacher.SetThumbnailsPaused(false);
+	EXPECT_GE(stop_spy.count(), 1);
+
+	QCoreApplication::processEvents();
+
+	cacher.SetProject(nullptr);
+}
+
+// With a project set, GetSingleFrame resolves the node through the ProjectCopier
+// and dispatches a real render ticket. With the dummy backend the underlying
+// ticket finishes without a result, and the passthrough ticket must be finished
+// once the watcher signals completion.
+TEST_F(RenderTailAutoCacherTest, GetSingleFrameDispatchesThroughProjectCopy)
+{
+	olive::ViewerOutput *viewer = CreateViewerWithParams();
+
+	auto *solid = new olive::SolidGenerator();
+	solid->setParent(project_.get());
+
+	olive::PreviewAutoCacher cacher;
+	cacher.SetProject(project_.get());
+
+	olive::RenderTicketPtr ticket =
+		cacher.GetSingleFrame(solid, viewer, olive::rational(0));
+	ASSERT_NE(ticket, nullptr);
+	EXPECT_TRUE(ticket->IsRunning());
+
+	// The dummy backend has no render threads, so the dispatched ticket can
+	// only be finished through the clear path (covered in detail by the
+	// ClearSingleFrameRenders tests below).
+	cacher.ClearSingleFrameRenders();
+
+	EXPECT_EQ(ticket->GetFinishCount(), 1);
+	EXPECT_FALSE(ticket->IsRunning());
+	EXPECT_FALSE(ticket->HasResult());
+
+	cacher.SetProject(nullptr);
+}
+
+// ClearSingleFrameRenders must cancel every dispatched (but no longer running)
+// single-frame passthrough: the ticket is finished without a result and the
+// watcher is reaped synchronously through VideoRendered.
+TEST_F(RenderTailAutoCacherTest, ClearSingleFrameRendersFinishesDispatchedTicket)
+{
+	olive::ViewerOutput *viewer = CreateViewerWithParams();
+
+	auto *solid = new olive::SolidGenerator();
+	solid->setParent(project_.get());
+
+	olive::PreviewAutoCacher cacher;
+	cacher.SetProject(project_.get());
+
+	olive::RenderTicketPtr ticket =
+		cacher.GetSingleFrame(solid, viewer, olive::rational(0));
+	ASSERT_NE(ticket, nullptr);
+	ASSERT_TRUE(ticket->IsRunning());
+
+	cacher.ClearSingleFrameRenders();
+
+	EXPECT_EQ(ticket->GetFinishCount(), 1);
+	EXPECT_FALSE(ticket->IsRunning());
+	EXPECT_FALSE(ticket->HasResult());
+
+	// Flush the stale queued watcher notification (its receiver is gone now).
+	QCoreApplication::processEvents();
+
+	cacher.SetProject(nullptr);
+}
+
+// ClearSingleFrameRendersThatArentRunning follows the same path for the dummy
+// backend, whose tickets are never running by the time they can be cleared.
+TEST_F(RenderTailAutoCacherTest,
+	   ClearSingleFrameRendersThatArentRunningFinishesDispatchedTicket)
+{
+	olive::ViewerOutput *viewer = CreateViewerWithParams();
+
+	auto *solid = new olive::SolidGenerator();
+	solid->setParent(project_.get());
+
+	olive::PreviewAutoCacher cacher;
+	cacher.SetProject(project_.get());
+
+	olive::RenderTicketPtr ticket =
+		cacher.GetSingleFrame(solid, viewer, olive::rational(0));
+	ASSERT_NE(ticket, nullptr);
+	ASSERT_TRUE(ticket->IsRunning());
+
+	cacher.ClearSingleFrameRendersThatArentRunning();
+
+	EXPECT_EQ(ticket->GetFinishCount(), 1);
+	EXPECT_FALSE(ticket->IsRunning());
+	EXPECT_FALSE(ticket->HasResult());
+
+	QCoreApplication::processEvents();
+
+	cacher.SetProject(nullptr);
+}
+
+class RenderTailDiskCacheTest : public ::testing::Test {
+protected:
+	void SetUp() override
+	{
+		if (!temp_dir_.isValid()) {
+			GTEST_FAIL() << "Failed to create temporary directory";
+		}
+
+		if (!olive::Core::instance()) {
+			// Leaked intentionally: matches render_diskcache_test, Core is
+			// process-wide and eviction paths call Core::WarnCacheFull().
+			new olive::Core(olive::Core::CoreParams());
+		}
+
+		olive::DiskManager::CreateInstance();
+	}
+
+	void TearDown() override
+	{
+		olive::DiskManager::DestroyInstance();
+	}
+
+	QString MakeSubDir(const QString &name) const
+	{
+		QDir root(temp_dir_.path());
+		if (!root.mkpath(name)) {
+			return QString();
+		}
+		return root.filePath(name);
+	}
+
+	QTemporaryDir temp_dir_;
+};
+
+// Moving a folder to a new path must broadcast DeletedFrame for every tracked
+// file (without deleting anything on disk) and reset the folder state to
+// defaults before loading the new path's index.
+TEST_F(RenderTailDiskCacheTest, SetPathEmitsDeletedFramesAndResetsState)
+{
+	const QString sub1 = MakeSubDir(QStringLiteral("move_from"));
+	const QString sub2 = MakeSubDir(QStringLiteral("move_to"));
+	ASSERT_FALSE(sub1.isEmpty());
+	ASSERT_FALSE(sub2.isEmpty());
+
+	olive::DiskCacheFolder folder(sub1);
+	folder.SetLimit(12345);
+
+	const QString fn = QDir(sub1).filePath(QStringLiteral("frame"));
+	ASSERT_TRUE(WriteFile(fn, 64));
+	folder.CreatedFile(fn);
+
+	QSignalSpy spy(&folder, &olive::DiskCacheFolder::DeletedFrame);
+
+	folder.SetPath(sub2);
+
+	EXPECT_EQ(folder.GetPath(), sub2);
+	EXPECT_EQ(folder.GetLimit(), 21474836480LL); // back to the 20 GB default
+	EXPECT_FALSE(folder.GetClearOnClose());
+
+	ASSERT_EQ(spy.count(), 1);
+	const QList<QVariant> args = spy.takeFirst();
+	EXPECT_EQ(args.at(0).toString(), sub1);
+	EXPECT_EQ(args.at(1).toString(), fn);
+
+	// The file itself is untouched, but it is no longer tracked
+	EXPECT_TRUE(QFileInfo::exists(fn));
+	EXPECT_FALSE(folder.DeleteSpecificFile(fn));
+}
+
+// When the persisted index references files that have since been deleted
+// externally, those entries must be skipped on load while surviving files are
+// still picked up.
+TEST_F(RenderTailDiskCacheTest, PersistedIndexSkipsFilesThatNoLongerExist)
+{
+	const QString sub = MakeSubDir(QStringLiteral("index_skip"));
+	ASSERT_FALSE(sub.isEmpty());
+
+	const QString keep = QDir(sub).filePath(QStringLiteral("keep"));
+	const QString gone = QDir(sub).filePath(QStringLiteral("gone"));
+	ASSERT_TRUE(WriteFile(keep, 32));
+	ASSERT_TRUE(WriteFile(gone, 32));
+
+	{
+		olive::DiskCacheFolder folder(sub);
+		folder.CreatedFile(keep);
+		folder.CreatedFile(gone);
+		// Destruction writes the index file into the cache folder
+	}
+
+	ASSERT_TRUE(QFile::remove(gone));
+
+	{
+		olive::DiskCacheFolder reopened(sub);
+
+		// The missing file was not re-registered, the surviving one was
+		EXPECT_TRUE(reopened.DeleteSpecificFile(keep));
+		EXPECT_FALSE(reopened.DeleteSpecificFile(gone));
+		EXPECT_FALSE(QFileInfo::exists(keep));
+	}
+}
+
+// The clear-on-close flag is serialized into the index along with the limit,
+// so a folder reopened after closing with the flag set must restore it.
+TEST_F(RenderTailDiskCacheTest, ClearOnCloseFlagPersistsAcrossInstances)
+{
+	const QString sub = MakeSubDir(QStringLiteral("persist_clear_flag"));
+	ASSERT_FALSE(sub.isEmpty());
+
+	const QString fn = QDir(sub).filePath(QStringLiteral("frame"));
+	ASSERT_TRUE(WriteFile(fn, 32));
+
+	{
+		olive::DiskCacheFolder folder(sub);
+		folder.SetClearOnClose(true);
+		folder.CreatedFile(fn);
+		// Destruction clears the cache and saves the flag into the index
+	}
+
+	ASSERT_FALSE(QFileInfo::exists(fn));
+
+	{
+		olive::DiskCacheFolder reopened(sub);
+		EXPECT_TRUE(reopened.GetClearOnClose());
+
+		// The cleared entry must not come back through the index either
+		EXPECT_FALSE(reopened.DeleteSpecificFile(fn));
+	}
+}
+
+// Registering a file that does not exist on disk tracks it with size zero;
+// deleting it again succeeds because a missing file counts as deleted.
+TEST_F(RenderTailDiskCacheTest, CreatedFileForMissingFileIsTrackedAsZeroSize)
+{
+	const QString sub = MakeSubDir(QStringLiteral("zero_size"));
+	ASSERT_FALSE(sub.isEmpty());
+
+	olive::DiskCacheFolder folder(sub);
+
+	const QString ghost = QDir(sub).filePath(QStringLiteral("ghost"));
+	ASSERT_FALSE(QFileInfo::exists(ghost));
+	folder.CreatedFile(ghost);
+
+	QSignalSpy spy(&folder, &olive::DiskCacheFolder::DeletedFrame);
+
+	EXPECT_TRUE(folder.DeleteSpecificFile(ghost));
+
+	ASSERT_EQ(spy.count(), 1);
+	EXPECT_EQ(spy.first().at(0).toString(), sub);
+	EXPECT_EQ(spy.first().at(1).toString(), ghost);
+}
+
+// DiskManager::Accessed/CreatedFile forward to the matching folder and
+// DeleteSpecificFile broadcasts to every open folder, re-emitting the folder's
+// DeletedFrame signal as its own.
+TEST_F(RenderTailDiskCacheTest,
+	   DiskManagerAccessedAndDeleteSpecificFileForwardToFolder)
+{
+	olive::DiskManager *dm = olive::DiskManager::instance();
+	ASSERT_NE(dm, nullptr);
+
+	const QString sub = MakeSubDir(QStringLiteral("forwarding"));
+	ASSERT_FALSE(sub.isEmpty());
+
+	const QString fn = QDir(sub).filePath(QStringLiteral("frame"));
+	ASSERT_TRUE(WriteFile(fn, 32));
+
+	dm->CreatedFile(sub, fn);
+	dm->Accessed(sub, fn);
+	ASSERT_TRUE(QFileInfo::exists(fn));
+
+	QSignalSpy spy(dm, &olive::DiskManager::DeletedFrame);
+
+	dm->DeleteSpecificFile(fn);
+
+	EXPECT_FALSE(QFileInfo::exists(fn));
+	ASSERT_EQ(spy.count(), 1);
+	EXPECT_EQ(spy.first().at(0).toString(), sub);
+	EXPECT_EQ(spy.first().at(1).toString(), fn);
+}
+
+// The static path helpers must return distinct, non-empty locations; the config
+// file name is part of the on-disk format.
+TEST_F(RenderTailDiskCacheTest, DefaultDiskCachePathsAreNonEmptyAndDistinct)
+{
+	const QString config_file =
+		olive::DiskManager::GetDefaultDiskCacheConfigFile();
+	const QString cache_path = olive::DiskManager::GetDefaultDiskCachePath();
+
+	EXPECT_FALSE(config_file.isEmpty());
+	EXPECT_FALSE(cache_path.isEmpty());
+	EXPECT_NE(config_file, cache_path);
+	EXPECT_TRUE(config_file.endsWith(QStringLiteral("defaultdiskcache")));
+}
+
+class RenderTailAudioCacheTest : public ::testing::Test {
+protected:
+	void SetUp() override
+	{
+		if (!temp_dir_.isValid()) {
+			GTEST_FAIL() << "Failed to create temporary directory";
+		}
+
+		if (!olive::Core::instance()) {
+			new olive::Core(olive::Core::CoreParams()); // intentionally leaked
+		}
+
+		olive::DiskManager::CreateInstance();
+
+		// Point the project cache at a folder alongside the (unsaved) project
+		// file so every cache write stays inside the temporary directory.
+		olive::ColorManager::SetUpDefaultConfig();
+		project_ = std::make_unique<olive::Project>();
+		project_->Initialize();
+		project_->set_filename(
+			QDir(temp_dir_.path()).filePath(QStringLiteral("test.ove")));
+		project_->SetCacheLocationSetting(
+			olive::Project::kCacheStoreAlongsideProject);
+	}
+
+	void TearDown() override
+	{
+		project_.reset();
+		olive::DiskManager::DestroyInstance();
+	}
+
+	static olive::core::AudioParams MakeParams()
+	{
+		return olive::core::AudioParams(48000,
+										olive::core::kChannelLayoutStereo,
+										olive::core::SampleFormat::F32P);
+	}
+
+	static void FillBuffer(olive::core::SampleBuffer *buf, float ch0, float ch1)
+	{
+		for (size_t i = 0; i < buf->sample_count(); i++) {
+			buf->data(0)[i] = ch0;
+			buf->data(1)[i] = ch1;
+		}
+	}
+
+	QTemporaryDir temp_dir_;
+	std::unique_ptr<olive::Project> project_;
+};
+
+// SetParameters stores the audio params; setting the same value twice early-outs
+// and leaves them untouched.
+TEST_F(RenderTailAudioCacheTest, SetParametersRoundTrip)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	EXPECT_EQ(cache.GetParameters().channel_count(), 0);
+
+	const olive::core::AudioParams params = MakeParams();
+	cache.SetParameters(params);
+	EXPECT_EQ(cache.GetParameters(), params);
+
+	cache.SetParameters(params);
+	EXPECT_EQ(cache.GetParameters(), params);
+
+	const olive::core::AudioParams other(44100,
+										 olive::core::kChannelLayoutMono,
+										 olive::core::SampleFormat::F32P);
+	cache.SetParameters(other);
+	EXPECT_EQ(cache.GetParameters().sample_rate(), 44100);
+	EXPECT_EQ(cache.GetParameters().channel_count(), 1);
+}
+
+// WritePCM writes one segment file per channel, zero-padded to the full segment
+// size, and validates exactly the written range.
+TEST_F(RenderTailAudioCacheTest, WritePcmWritesSegmentFilesAndValidatesRange)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	cache.SetParameters(MakeParams());
+
+	const olive::TimeRange range(olive::rational(0), olive::rational(1, 10));
+
+	olive::core::SampleBuffer buf(MakeParams(), olive::rational(1, 10));
+	ASSERT_TRUE(buf.is_allocated());
+	FillBuffer(&buf, 0.5f, 0.25f);
+
+	cache.WritePCM(range, { range }, buf);
+
+	EXPECT_TRUE(cache.HasValidatedRanges());
+	EXPECT_FALSE(cache.HasInvalidatedRanges(range));
+
+	// 4800 samples of 4-byte floats per channel
+	const qint64 data_bytes = 19200;
+
+	const QDir seg_dir = cache.GetThisCacheDirectory();
+	const QString ch0 = seg_dir.filePath(QStringLiteral("0.0"));
+	const QString ch1 = seg_dir.filePath(QStringLiteral("0.1"));
+	ASSERT_TRUE(QFileInfo::exists(ch0));
+	ASSERT_TRUE(QFileInfo::exists(ch1));
+
+	// The buffer covered the whole range, so no padding is needed and the
+	// segment contains exactly the written data
+	EXPECT_EQ(QFileInfo(ch0).size(), data_bytes);
+	EXPECT_EQ(QFileInfo(ch1).size(), data_bytes);
+
+	QByteArray bytes;
+	ASSERT_TRUE(ReadBytesAt(ch0, 0, 4, &bytes));
+	EXPECT_FLOAT_EQ(BytesToFloat(bytes), 0.5f);
+
+	ASSERT_TRUE(ReadBytesAt(ch1, 0, 4, &bytes));
+	EXPECT_FLOAT_EQ(BytesToFloat(bytes), 0.25f);
+}
+
+// A write that does not start at zero must seek into the segment, leaving the
+// preceding bytes as silence.
+TEST_F(RenderTailAudioCacheTest, WritePcmAtNonZeroStartWritesAtByteOffset)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	cache.SetParameters(MakeParams());
+
+	const olive::TimeRange range(olive::rational(1, 10), olive::rational(1, 5));
+
+	olive::core::SampleBuffer buf(MakeParams(), olive::rational(1, 10));
+	ASSERT_TRUE(buf.is_allocated());
+	FillBuffer(&buf, 0.75f, 0.75f);
+
+	cache.WritePCM(range, { range }, buf);
+
+	EXPECT_FALSE(cache.HasInvalidatedRanges(range));
+
+	const qint64 data_bytes = 19200;
+	const QString ch0 =
+		cache.GetThisCacheDirectory().filePath(QStringLiteral("0.0"));
+	ASSERT_TRUE(QFileInfo::exists(ch0));
+	// The file extends exactly to the end of the written range
+	EXPECT_EQ(QFileInfo(ch0).size(), 2 * data_bytes);
+
+	// The first range was never written, so it reads back as silence
+	QByteArray bytes;
+	ASSERT_TRUE(ReadBytesAt(ch0, 0, 4, &bytes));
+	EXPECT_EQ(bytes, QByteArray(4, '\0'));
+
+	// The new data starts exactly at its byte offset
+	ASSERT_TRUE(ReadBytesAt(ch0, data_bytes, 4, &bytes));
+	EXPECT_FLOAT_EQ(BytesToFloat(bytes), 0.75f);
+}
+
+// Only the listed valid ranges are validated, even when the sample buffer
+// covers the whole render range.
+TEST_F(RenderTailAudioCacheTest, WritePcmWithPartialValidRangesValidatesOnlyThose)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	cache.SetParameters(MakeParams());
+
+	const olive::TimeRange range(olive::rational(0), olive::rational(1, 5));
+	const olive::TimeRange first_half(olive::rational(0), olive::rational(1, 10));
+
+	olive::core::SampleBuffer buf(MakeParams(), olive::rational(1, 5));
+	ASSERT_TRUE(buf.is_allocated());
+	FillBuffer(&buf, 0.5f, 0.5f);
+
+	cache.WritePCM(range, { first_half }, buf);
+
+	EXPECT_FALSE(cache.HasInvalidatedRanges(first_half));
+	EXPECT_TRUE(cache.HasInvalidatedRanges(range));
+}
+
+// An empty valid-range list writes no segments and validates nothing.
+TEST_F(RenderTailAudioCacheTest, WritePcmWithNoValidRangesWritesNothing)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	cache.SetParameters(MakeParams());
+
+	const olive::TimeRange range(olive::rational(0), olive::rational(1, 10));
+
+	olive::core::SampleBuffer buf(MakeParams(), olive::rational(1, 10));
+	ASSERT_TRUE(buf.is_allocated());
+
+	cache.WritePCM(range, olive::TimeRangeList(), buf);
+
+	EXPECT_FALSE(cache.HasValidatedRanges());
+	EXPECT_FALSE(QFileInfo::exists(
+		cache.GetThisCacheDirectory().filePath(QStringLiteral("0.0"))));
+}
+
+// A write larger than one segment must spill into the next segment file, with
+// each touched segment zero-padded to its full extent.
+TEST_F(RenderTailAudioCacheTest,
+	   WritePcmSpanningSegmentBoundaryCreatesBothSegments)
+{
+	olive::AudioPlaybackCache cache(project_.get());
+	cache.SetParameters(MakeParams());
+
+	// 56 seconds at 48000 Hz is 10752000 bytes per channel, just over one
+	// 10 MB segment.
+	const olive::TimeRange range(olive::rational(0), olive::rational(56));
+
+	olive::core::SampleBuffer buf(MakeParams(), olive::rational(56));
+	ASSERT_TRUE(buf.is_allocated());
+	ASSERT_EQ(buf.sample_count(), size_t(56 * 48000));
+	FillBuffer(&buf, 1.0f, 1.0f);
+
+	cache.WritePCM(range, { range }, buf);
+
+	EXPECT_FALSE(cache.HasInvalidatedRanges(range));
+
+	const QDir seg_dir = cache.GetThisCacheDirectory();
+	const QString seg0 = seg_dir.filePath(QStringLiteral("0.0"));
+	const QString seg1 = seg_dir.filePath(QStringLiteral("1.0"));
+	ASSERT_TRUE(QFileInfo::exists(seg0));
+	ASSERT_TRUE(QFileInfo::exists(seg1));
+
+	EXPECT_EQ(QFileInfo(seg0).size(), kSegmentSize);
+	// The second segment holds exactly the spillover bytes
+	EXPECT_EQ(QFileInfo(seg1).size(),
+			  56 * 48000 * 4 - kSegmentSize);
+
+	// The spillover data starts at the beginning of the second segment file
+	QByteArray bytes;
+	ASSERT_TRUE(ReadBytesAt(seg1, 0, 4, &bytes));
+	EXPECT_FLOAT_EQ(BytesToFloat(bytes), 1.0f);
+}