test: add image attachment regression coverage

src/gateway/chat-attachments.test.ts

@@ -59,6 +59,59 @@ describe("buildMessageWithAttachments", () => {
 });
 
 describe("parseMessageWithAttachments", () => {
+  it("strips data URL prefix", async () => {
+    const parsed = await parseMessageWithAttachments(
+      "see this",
+      [
+        {
+          type: "image",
+          mimeType: "image/png",
+          fileName: "dot.png",
+          content: `data:image/png;base64,${PNG_1x1}`,
+        },
+      ],
+      { log: { warn: () => {} } },
+    );
+    expect(parsed.images).toHaveLength(1);
+    expect(parsed.images[0]?.mimeType).toBe("image/png");
+    expect(parsed.images[0]?.data).toBe(PNG_1x1);
+  });
+
+  it("rejects invalid base64 content", async () => {
+    await expect(
+      parseMessageWithAttachments(
+        "x",
+        [
+          {
+            type: "image",
+            mimeType: "image/png",
+            fileName: "dot.png",
+            content: "%not-base64%",
+          },
+        ],
+        { log: { warn: () => {} } },
+      ),
+    ).rejects.toThrow(/base64/i);
+  });
+
+  it("rejects images over limit", async () => {
+    const big = Buffer.alloc(6_000_000, 0).toString("base64");
+    await expect(
+      parseMessageWithAttachments(
+        "x",
+        [
+          {
+            type: "image",
+            mimeType: "image/png",
+            fileName: "big.png",
+            content: big,
+          },
+        ],
+        { maxBytes: 5_000_000, log: { warn: () => {} } },
+      ),
+    ).rejects.toThrow(/exceeds size limit/i);
+  });
+
   it("sniffs mime when missing", async () => {
     const logs: string[] = [];
     const parsed = await parseMessageWithAttachments(
@@ -118,4 +171,44 @@ describe("parseMessageWithAttachments", () => {
     expect(logs).toHaveLength(1);
     expect(logs[0]).toMatch(/mime mismatch/i);
   });
+
+  it("drops unknown mime when sniff fails and logs", async () => {
+    const logs: string[] = [];
+    const unknown = Buffer.from("not an image").toString("base64");
+    const parsed = await parseMessageWithAttachments(
+      "x",
+      [{ type: "file", fileName: "unknown.bin", content: unknown }],
+      { log: { warn: (message) => logs.push(message) } },
+    );
+    expect(parsed.images).toHaveLength(0);
+    expect(logs).toHaveLength(1);
+    expect(logs[0]).toMatch(/unable to detect image mime type/i);
+  });
+
+  it("keeps valid images and drops invalid ones", async () => {
+    const logs: string[] = [];
+    const pdf = Buffer.from("%PDF-1.4\n").toString("base64");
+    const parsed = await parseMessageWithAttachments(
+      "x",
+      [
+        {
+          type: "image",
+          mimeType: "image/png",
+          fileName: "dot.png",
+          content: PNG_1x1,
+        },
+        {
+          type: "file",
+          mimeType: "image/png",
+          fileName: "not-image.pdf",
+          content: pdf,
+        },
+      ],
+      { log: { warn: (message) => logs.push(message) } },
+    );
+    expect(parsed.images).toHaveLength(1);
+    expect(parsed.images[0]?.mimeType).toBe("image/png");
+    expect(parsed.images[0]?.data).toBe(PNG_1x1);
+    expect(logs.some((l) => /non-image/i.test(l))).toBe(true);
+  });
 });