diff --git a/extensions/codex/src/app-server/plugin-thread-config.test.ts b/extensions/codex/src/app-server/plugin-thread-config.test.ts
index 8ed84af785a..08fe1bf8e7c 100644
--- a/extensions/codex/src/app-server/plugin-thread-config.test.ts
+++ b/extensions/codex/src/app-server/plugin-thread-config.test.ts
@@ -393,9 +393,7 @@ describe("Codex plugin thread config", () => {
     });
     expect(config.diagnostics).toEqual([]);
     expect(request.mock.calls.map(([method]) => method)).toContain("plugin/install");
-    expect(request.mock.calls.filter(([method]) => method === "app/list").length).toBeGreaterThan(
-      0,
-    );
+    expect(request.mock.calls.some(([method]) => method === "app/list")).toBe(true);
     expect(appListParams.map((params) => params.forceRefetch)).toContain(true);
   });
 
diff --git a/extensions/google/oauth.test.ts b/extensions/google/oauth.test.ts
index 03c99d3a547..1274fffa620 100644
--- a/extensions/google/oauth.test.ts
+++ b/extensions/google/oauth.test.ts
@@ -46,6 +46,16 @@ const mockReaddirSync = vi.fn();
 const mockSettingsExistsSync = vi.fn();
 const mockSettingsReadFileSync = vi.fn();
 
+function countMatching<T>(items: readonly T[], predicate: (item: T) => boolean): number {
+  let count = 0;
+  for (const item of items) {
+    if (predicate(item)) {
+      count += 1;
+    }
+  }
+  return count;
+}
+
 describe("resolveGeminiCliSelectedAuthType", () => {
   const ENV_KEYS = ["GOOGLE_GENAI_USE_GCA"] as const;
 
@@ -843,7 +853,7 @@ describe("loginGeminiCliOAuth", () => {
     });
 
     await runProjectDiscoveryExpectingProjectId("env-project");
-    expect(requests.filter(({ url }) => url.includes("v1internal:loadCodeAssist"))).toHaveLength(3);
+    expect(countMatching(requests, ({ url }) => url.includes("v1internal:loadCodeAssist"))).toBe(3);
     expect(requests.map(({ url }) => url)).not.toEqual(
       expect.arrayContaining([expect.stringContaining("v1internal:onboardUser")]),
     );
diff --git a/extensions/memory-wiki/src/bridge.test.ts b/extensions/memory-wiki/src/bridge.test.ts
index 54e9b0eeab1..ec98804c4d9 100644
--- a/extensions/memory-wiki/src/bridge.test.ts
+++ b/extensions/memory-wiki/src/bridge.test.ts
@@ -128,7 +128,9 @@ describe("syncMemoryWikiBridgeSources", () => {
     expect(first.pagePaths).toHaveLength(3);
 
     const sourcePages = await fs.readdir(path.join(vaultDir, "sources"));
-    expect(sourcePages.filter((name) => name.startsWith("bridge-"))).toHaveLength(3);
+    expect(
+      sourcePages.reduce((count, name) => count + (name.startsWith("bridge-") ? 1 : 0), 0),
+    ).toBe(3);
 
     const memoryPage = await fs.readFile(path.join(vaultDir, first.pagePaths[0] ?? ""), "utf8");
     expect(memoryPage).toContain("sourceType: memory-bridge");
diff --git a/extensions/qa-matrix/src/substrate/harness.runtime.test.ts b/extensions/qa-matrix/src/substrate/harness.runtime.test.ts
index 39873474285..e25546ca8c9 100644
--- a/extensions/qa-matrix/src/substrate/harness.runtime.test.ts
+++ b/extensions/qa-matrix/src/substrate/harness.runtime.test.ts
@@ -45,6 +45,16 @@ function createContainerNetworkRunCommand(calls?: string[]) {
   };
 }
 
+function countMatching<T>(items: readonly T[], predicate: (item: T) => boolean): number {
+  let count = 0;
+  for (const item of items) {
+    if (predicate(item)) {
+      count += 1;
+    }
+  }
+  return count;
+}
+
 describe("matrix harness runtime", () => {
   it("writes a pinned Tuwunel compose file and redacted manifest", async () => {
     const outputDir = await mkdtemp(path.join(os.tmpdir(), "matrix-qa-harness-"));
@@ -180,7 +190,7 @@ describe("matrix harness runtime", () => {
           return {
             ok:
               input === "http://127.0.0.1:28008/_matrix/client/versions" &&
-              fetchCalls.filter((url) => url === input).length > 1,
+              countMatching(fetchCalls, (url) => url === input) > 1,
           };
         }),
         sleepImpl: vi.fn(async () => {}),
@@ -208,7 +218,7 @@ describe("matrix harness runtime", () => {
           return {
             ok:
               input === "http://172.18.0.10:8008/_matrix/client/versions" &&
-              fetchCalls.filter((url) => url === input).length > 1,
+              countMatching(fetchCalls, (url) => url === input) > 1,
           };
         }),
         sleepImpl: vi.fn(async () => {}),
diff --git a/extensions/synology-chat/src/webhook-handler.test.ts b/extensions/synology-chat/src/webhook-handler.test.ts
index a69a801f705..07330148fe9 100644
--- a/extensions/synology-chat/src/webhook-handler.test.ts
+++ b/extensions/synology-chat/src/webhook-handler.test.ts
@@ -16,6 +16,16 @@ type TestLog = {
   error: (...args: unknown[]) => void;
 };
 
+function countMatching<T>(items: readonly T[], predicate: (item: T) => boolean): number {
+  let count = 0;
+  for (const item of items) {
+    if (predicate(item)) {
+      count += 1;
+    }
+  }
+  return count;
+}
+
 function makeAccount(
   overrides: Partial<ResolvedSynologyChatAccount> = {},
 ): ResolvedSynologyChatAccount {
@@ -240,8 +250,8 @@ describe("createWebhookHandler", () => {
     await new Promise((resolve) => setTimeout(resolve, 0));
 
     // Default maxInFlightPerKey is 8; 12 total requests leaves 4 rejected with 429.
-    expect(responses.filter((res) => res._status === 0)).toHaveLength(8);
-    expect(responses.filter((res) => res._status === 429)).toHaveLength(4);
+    expect(countMatching(responses, (res) => res._status === 0)).toBe(8);
+    expect(countMatching(responses, (res) => res._status === 429)).toBe(4);
 
     for (const req of requests) {
       req.emit("end");