perf(test): reduce module reload churn in unit suites

src/slack/monitor/media.test.ts

@@ -1,5 +1,7 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import * as ssrf from "../../infra/net/ssrf.js";
+import * as mediaStore from "../../media/store.js";
+import { fetchWithSlackAuth, resolveSlackMedia, resolveSlackThreadHistory } from "./media.js";
 
 // Store original fetch
 const originalFetch = globalThis.fetch;
@@ -15,13 +17,9 @@ describe("fetchWithSlackAuth", () => {
   afterEach(() => {
     // Restore original fetch
     globalThis.fetch = originalFetch;
-    vi.resetModules();
   });
 
   it("sends Authorization header on initial request with manual redirect", async () => {
-    // Import after mocking fetch
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     // Simulate direct 200 response (no redirect)
     const mockResponse = new Response(Buffer.from("image data"), {
       status: 200,
@@ -42,8 +40,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("rejects non-Slack hosts to avoid leaking tokens", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     await expect(
       fetchWithSlackAuth("https://example.com/test.jpg", "xoxb-test-token"),
     ).rejects.toThrow(/non-Slack host|non-Slack/i);
@@ -53,8 +49,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("follows redirects without Authorization header", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     // First call: redirect response from Slack
     const redirectResponse = new Response(null, {
       status: 302,
@@ -89,8 +83,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("handles relative redirect URLs", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     // Redirect with relative URL
     const redirectResponse = new Response(null, {
       status: 302,
@@ -113,8 +105,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("returns redirect response when no location header is provided", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     // Redirect without location header
     const redirectResponse = new Response(null, {
       status: 302,
@@ -131,8 +121,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("returns 4xx/5xx responses directly without following", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     const errorResponse = new Response("Not Found", {
       status: 404,
     });
@@ -146,8 +134,6 @@ describe("fetchWithSlackAuth", () => {
   });
 
   it("handles 301 permanent redirects", async () => {
-    const { fetchWithSlackAuth } = await import("./media.js");
-
     const redirectResponse = new Response(null, {
       status: 301,
       headers: { location: "https://cdn.slack.com/new-url" },
@@ -185,20 +171,14 @@ describe("resolveSlackMedia", () => {
 
   afterEach(() => {
     globalThis.fetch = originalFetch;
-    vi.resetModules();
     vi.restoreAllMocks();
   });
 
   it("prefers url_private_download over url_private", async () => {
-    // Mock the store module
-    vi.doMock("../../media/store.js", () => ({
-      saveMediaBuffer: vi.fn().mockResolvedValue({
-        path: "/tmp/test.jpg",
-        contentType: "image/jpeg",
-      }),
-    }));
-
-    const { resolveSlackMedia } = await import("./media.js");
+    vi.spyOn(mediaStore, "saveMediaBuffer").mockResolvedValue({
+      path: "/tmp/test.jpg",
+      contentType: "image/jpeg",
+    });
 
     const mockResponse = new Response(Buffer.from("image data"), {
       status: 200,
@@ -225,8 +205,6 @@ describe("resolveSlackMedia", () => {
   });
 
   it("returns null when download fails", async () => {
-    const { resolveSlackMedia } = await import("./media.js");
-
     // Simulate a network error
     mockFetch.mockRejectedValueOnce(new Error("Network error"));
 
@@ -240,8 +218,6 @@ describe("resolveSlackMedia", () => {
   });
 
   it("returns null when no files are provided", async () => {
-    const { resolveSlackMedia } = await import("./media.js");
-
     const result = await resolveSlackMedia({
       files: [],
       token: "xoxb-test-token",
@@ -252,8 +228,6 @@ describe("resolveSlackMedia", () => {
   });
 
   it("skips files without url_private", async () => {
-    const { resolveSlackMedia } = await import("./media.js");
-
     const result = await resolveSlackMedia({
       files: [{ name: "test.jpg" }], // No url_private
       token: "xoxb-test-token",
@@ -265,15 +239,10 @@ describe("resolveSlackMedia", () => {
   });
 
   it("falls through to next file when first file returns error", async () => {
-    // Mock the store module
-    vi.doMock("../../media/store.js", () => ({
-      saveMediaBuffer: vi.fn().mockResolvedValue({
-        path: "/tmp/test.jpg",
-        contentType: "image/jpeg",
-      }),
-    }));
-
-    const { resolveSlackMedia } = await import("./media.js");
+    vi.spyOn(mediaStore, "saveMediaBuffer").mockResolvedValue({
+      path: "/tmp/test.jpg",
+      contentType: "image/jpeg",
+    });
 
     // First file: 404
     const errorResponse = new Response("Not Found", { status: 404 });
@@ -301,7 +270,6 @@ describe("resolveSlackMedia", () => {
 
 describe("resolveSlackThreadHistory", () => {
   afterEach(() => {
-    vi.resetModules();
     vi.restoreAllMocks();
   });
 
@@ -324,7 +292,6 @@ describe("resolveSlackThreadHistory", () => {
         })),
         response_metadata: { next_cursor: "" },
       });
-    const { resolveSlackThreadHistory } = await import("./media.js");
     const client = {
       conversations: { replies },
     } as Parameters<typeof resolveSlackThreadHistory>[0]["client"];
@@ -375,7 +342,6 @@ describe("resolveSlackThreadHistory", () => {
       ],
       response_metadata: { next_cursor: "" },
     });
-    const { resolveSlackThreadHistory } = await import("./media.js");
     const client = {
       conversations: { replies },
     } as Parameters<typeof resolveSlackThreadHistory>[0]["client"];
@@ -394,7 +360,6 @@ describe("resolveSlackThreadHistory", () => {
 
   it("returns empty when limit is zero without calling Slack API", async () => {
     const replies = vi.fn();
-    const { resolveSlackThreadHistory } = await import("./media.js");
     const client = {
       conversations: { replies },
     } as Parameters<typeof resolveSlackThreadHistory>[0]["client"];
@@ -412,7 +377,6 @@ describe("resolveSlackThreadHistory", () => {
 
   it("returns empty when Slack API throws", async () => {
     const replies = vi.fn().mockRejectedValueOnce(new Error("slack down"));
-    const { resolveSlackThreadHistory } = await import("./media.js");
     const client = {
       conversations: { replies },
     } as Parameters<typeof resolveSlackThreadHistory>[0]["client"];