diff --git a/src/cli/update-cli.test.ts b/src/cli/update-cli.test.ts
index 2ca137835b1..b9e078199d2 100644
--- a/src/cli/update-cli.test.ts
+++ b/src/cli/update-cli.test.ts
@@ -34,12 +34,46 @@ vi.mock("../config/config.js", () => ({
   writeConfigFile: vi.fn(),
 }));
 
-vi.mock("../infra/update-check.js", async () => {
-  const actual = await vi.importActual<typeof import("../infra/update-check.js")>(
-    "../infra/update-check.js",
-  );
+vi.mock("../infra/update-check.js", () => {
+  const parseSemver = (
+    value: string | null,
+  ): { major: number; minor: number; patch: number } | null => {
+    if (!value) {
+      return null;
+    }
+    const m = /^(\d+)\.(\d+)\.(\d+)/.exec(value);
+    if (!m) {
+      return null;
+    }
+    const major = Number(m[1]);
+    const minor = Number(m[2]);
+    const patch = Number(m[3]);
+    if (!Number.isFinite(major) || !Number.isFinite(minor) || !Number.isFinite(patch)) {
+      return null;
+    }
+    return { major, minor, patch };
+  };
+
+  const compareSemverStrings = (a: string | null, b: string | null): number | null => {
+    const pa = parseSemver(a);
+    const pb = parseSemver(b);
+    if (!pa || !pb) {
+      return null;
+    }
+    if (pa.major !== pb.major) {
+      return pa.major < pb.major ? -1 : 1;
+    }
+    if (pa.minor !== pb.minor) {
+      return pa.minor < pb.minor ? -1 : 1;
+    }
+    if (pa.patch !== pb.patch) {
+      return pa.patch < pb.patch ? -1 : 1;
+    }
+    return 0;
+  };
+
   return {
-    ...actual,
+    compareSemverStrings,
     checkUpdateStatus: vi.fn(),
     fetchNpmTagVersion: vi.fn(),
     resolveNpmChannelTag: vi.fn(),