test(image-pipeline): add cpu webgl parity coverage

tests/image-pipeline/parity/cpu-webgl-parity.test.ts

@@ -0,0 +1,57 @@
+// @vitest-environment jsdom
+
+import { afterEach, describe, expect, it } from "vitest";
+
+import {
+  createParityPipelines,
+  evaluateCpuWebglParity,
+  installParityWebglContextMock,
+  parityTolerances,
+  restoreParityWebglContextMock,
+} from "@/tests/image-pipeline/parity/fixtures";
+
+describe("cpu vs webgl parity", () => {
+  afterEach(() => {
+    restoreParityWebglContextMock();
+  });
+
+  it("keeps curves-only pipeline within parity tolerance", () => {
+    const pipelines = createParityPipelines();
+    installParityWebglContextMock();
+
+    const metrics = evaluateCpuWebglParity(pipelines.curvesOnly);
+
+    expect(metrics.maxChannelDelta).toBeLessThanOrEqual(parityTolerances.curvesOnly.maxChannelDelta);
+    expect(metrics.histogramSimilarity).toBeGreaterThanOrEqual(
+      parityTolerances.curvesOnly.histogramSimilarity,
+    );
+  });
+
+  it("keeps color-adjust-only pipeline within parity tolerance", () => {
+    const pipelines = createParityPipelines();
+    installParityWebglContextMock();
+
+    const metrics = evaluateCpuWebglParity(pipelines.colorAdjustOnly);
+
+    expect(metrics.maxChannelDelta).toBeLessThanOrEqual(
+      parityTolerances.colorAdjustOnly.maxChannelDelta,
+    );
+    expect(metrics.histogramSimilarity).toBeGreaterThanOrEqual(
+      parityTolerances.colorAdjustOnly.histogramSimilarity,
+    );
+  });
+
+  it("keeps curves + color-adjust chain within parity tolerance", () => {
+    const pipelines = createParityPipelines();
+    installParityWebglContextMock();
+
+    const metrics = evaluateCpuWebglParity(pipelines.curvesPlusColorAdjust);
+
+    expect(metrics.maxChannelDelta).toBeLessThanOrEqual(
+      parityTolerances.curvesPlusColorAdjust.maxChannelDelta,
+    );
+    expect(metrics.histogramSimilarity).toBeGreaterThanOrEqual(
+      parityTolerances.curvesPlusColorAdjust.histogramSimilarity,
+    );
+  });
+});