test(wp7-02): require exact image normalization

tests/package/wp7-02-controlled-executor.test.mjs

@@ -93,7 +93,7 @@ test("TDD-WP7-EXT-001 builds protocol-specific requests without auth in argument
     model: "gpt-image-2",
     prompt: "controlled fixture prompt",
     response_format: "b64_json",
-    size: "1080x1920",
+    size: "1008x1792",
   });
   assert.equal("authorization" in openai.headers, false);
 });

tests/unit/wp7-02-image-output-normalizer.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  gptImageRequestSizeForRatio,
+  normalizeImageOutputToRatio,
+  productDimensionsForRatio,
+} from "../../apps/worker/src/image-output-normalizer.js";
+
+const onePixelPng = Buffer.from(
+  "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=",
+  "base64",
+);
+
+describe("TDD-WP7-EXT-001 exact image output normalization", () => {
+  it("uses only GPT Image 2 request sizes allowed by the upstream API", () => {
+    expect(["3:4", "1:1", "4:3", "9:16"].map((ratio) => gptImageRequestSizeForRatio(ratio))).toEqual([
+      "1056x1408",
+      "1088x1088",
+      "1408x1056",
+      "1008x1792",
+    ]);
+    for (const ratio of ["3:4", "1:1", "4:3", "9:16"] as const) {
+      const [width, height] = gptImageRequestSizeForRatio(ratio).split("x").map(Number);
+      expect(width % 16).toBe(0);
+      expect(height % 16).toBe(0);
+    }
+  });
+
+  it("normalizes provider output to the frozen product dimensions", async () => {
+    const output = await normalizeImageOutputToRatio({ bytes: onePixelPng, mimeType: "image/png", ratio: "1:1" });
+    expect(output).toMatchObject({
+      mimeType: "image/png",
+      normalized: true,
+      pixelHeight: 1080,
+      pixelWidth: 1080,
+      upstreamPixelHeight: 1,
+      upstreamPixelWidth: 1,
+    });
+    expect(output.bytes.subarray(0, 8).toString("hex")).toBe("89504e470d0a1a0a");
+    expect(productDimensionsForRatio("9:16")).toEqual({ pixelHeight: 1920, pixelWidth: 1080 });
+  });
+});