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, 28 insertions, 0 deletions

diff --git a/src/tests/common/effect_test_fixture.h b/src/tests/common/effect_test_fixture.h
new file mode 100644
index 0000000..399b5ed
--- /dev/null
+++ b/src/tests/common/effect_test_fixture.h
@@ -0,0 +1,28 @@
+// effect_test_fixture.h - Combined WebGPU + AudioEngine + MainSequence fixture
+// Simplifies GPU effect test setup
+
+#pragma once
+#include "webgpu_test_fixture.h"
+#include "audio_test_fixture.h"
+#include "gpu/sequence.h"
+
+// Combined WebGPU + AudioEngine + MainSequence fixture
+class EffectTestFixture {
+public:
+  EffectTestFixture();
+  ~EffectTestFixture();
+
+  // Returns false if GPU unavailable (test should skip)
+  bool init();
+
+  // Accessors
+  GpuContext ctx() const { return m_gpu.ctx(); }
+  MainSequence& sequence() { return m_sequence; }
+  AudioEngine& audio() { return m_audio.engine(); }
+
+private:
+  WebGPUTestFixture m_gpu;
+  AudioTestFixture m_audio;
+  MainSequence m_sequence;
+  bool m_initialized = false;
+};