Factor common test patterns into reusable utilitiesHEADmain

Refactor duplicated test setup/teardown code into shared fixtures:
- test_math_helpers.h: Float comparison (test_near, test_near_vec3)
- AudioTestFixture: RAII wrapper for AudioEngine lifecycle
- EffectTestFixture: Combined WebGPU + AudioEngine + MainSequence

Migrated 9 test files (3 math, 6 audio) to use fixtures.
Net reduction: 54 LOC (178 insertions, 232 deletions).

All 34 tests passing.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/tests/common/audio_test_fixture.h b/src/tests/common/audio_test_fixture.h
new file mode 100644
index 0000000..328e167
--- /dev/null
+++ b/src/tests/common/audio_test_fixture.h
@@ -0,0 +1,26 @@
+// audio_test_fixture.h - RAII wrapper for AudioEngine lifecycle
+// Simplifies audio test setup and teardown
+
+#pragma once
+#include "audio/audio_engine.h"
+#include "audio/gen.h"
+#include "audio/tracker.h"
+#include "generated/assets.h"
+
+// RAII wrapper for AudioEngine lifecycle
+class AudioTestFixture {
+public:
+  AudioTestFixture();  // Calls engine.init()
+  ~AudioTestFixture(); // Calls engine.shutdown()
+
+  AudioEngine& engine() { return m_engine; }
+
+  // Helper: Load tracker music data
+  void load_music(const TrackerScore* score,
+                  const NoteParams* samples,
+                  const AssetId* assets,
+                  uint32_t count);
+
+private:
+  AudioEngine m_engine;
+};