test: harden OpenAI response error handling

test/openai/responses.test.js

@@ -30,6 +30,18 @@ function makeNetworkError() {
   return err;
 }
 
+function makeServerError() {
+  const err = new Error("Service unavailable");
+  err.status = 503;
+  return err;
+}
+
+function makeTimeoutError() {
+  const err = new Error("timeout");
+  err.code = "ETIMEDOUT";
+  return err;
+}
+
 // --- Import ---
 
 const { sendOpenAIResponse } = await import("../../src/openai/responses.js");
@@ -167,4 +179,38 @@ describe("sendOpenAIResponse", () => {
       sendOpenAIResponse(mockClient, { input: ["x"], model: "m", maxOutputTokens: -5 })
     ).rejects.toHaveProperty("kind", "ValidationError");
   });
+
+  it("throws ValidationError when maxOutputTokens is zero", async () => {
+    await expect(
+      sendOpenAIResponse(mockClient, { input: ["x"], model: "m", maxOutputTokens: 0 })
+    ).rejects.toHaveProperty("kind", "ValidationError");
+  });
+
+  it("throws ValidationError when maxOutputTokens is a non-positive float", async () => {
+    await expect(
+      sendOpenAIResponse(mockClient, { input: ["x"], model: "m", maxOutputTokens: 0.5 })
+    ).rejects.toHaveProperty("kind", "ValidationError");
+  });
+
+  it("throws ValidationError when maxOutputTokens is NaN", async () => {
+    await expect(
+      sendOpenAIResponse(mockClient, { input: ["x"], model: "m", maxOutputTokens: NaN })
+    ).rejects.toHaveProperty("kind", "ValidationError");
+  });
+
+  // ===== Error mapping edge cases (2) =====
+
+  it("maps status 503 to OpenAIRequestError", async () => {
+    mockCreate.mockRejectedValueOnce(makeServerError());
+    await expect(
+      sendOpenAIResponse(mockClient, { input: ["x"], model: "m" })
+    ).rejects.toHaveProperty("kind", "OpenAIRequestError");
+  });
+
+  it("maps timeout error (code ETIMEDOUT) to OpenAIRequestError", async () => {
+    mockCreate.mockRejectedValueOnce(makeTimeoutError());
+    await expect(
+      sendOpenAIResponse(mockClient, { input: ["x"], model: "m" })
+    ).rejects.toHaveProperty("kind", "OpenAIRequestError");
+  });
 });