Coordinate a2amcp credential refresh

tests/oauth.test.ts

@@ -93,3 +93,89 @@ test("refreshCredentialsIfNeeded refreshes expired Keycloak access token", async
   assert.equal((await loadCredentials())!.token, "fresh-token");
   assert.ok(calls.some((call) => call.body?.includes("grant_type=refresh_token")));
 });
+
+test("refreshCredentialsIfNeeded serializes concurrent refreshes", async () => {
+  let tokenCalls = 0;
+  globalThis.fetch = (async (input: RequestInfo | URL) => {
+    const url = String(input);
+    if (url.endsWith("/.well-known/openid-configuration")) {
+      return new Response(
+        JSON.stringify({
+          authorization_endpoint: "https://auth.example.test/auth",
+          token_endpoint: "https://auth.example.test/token",
+        }),
+        { status: 200, headers: { "content-type": "application/json" } },
+      );
+    }
+    tokenCalls += 1;
+    await new Promise((resolve) => setTimeout(resolve, 25));
+    return new Response(
+      JSON.stringify({
+        access_token: `fresh-token-${tokenCalls}`,
+        refresh_token: `fresh-refresh-${tokenCalls}`,
+        expires_in: 3600,
+        scope: "openid email mcp:invoke",
+      }),
+      { status: 200, headers: { "content-type": "application/json" } },
+    );
+  }) as typeof fetch;
+
+  await saveCredentials({
+    apiUrl: "https://api.example.test",
+    token: "old-token",
+    refreshToken: "refresh-token",
+    expiresAt: 1,
+    email: "dev@example.test",
+    issuer: "https://auth.example.test",
+    clientId: "a2acloud-cli",
+  });
+
+  const stale = (await loadCredentials())!;
+  const [first, second] = await Promise.all([
+    refreshCredentialsIfNeeded(stale),
+    refreshCredentialsIfNeeded({ ...stale }),
+  ]);
+
+  assert.equal(tokenCalls, 1);
+  assert.equal(first.token, "fresh-token-1");
+  assert.equal(second.token, "fresh-token-1");
+  assert.equal((await loadCredentials())!.refreshToken, "fresh-refresh-1");
+});
+
+test("refreshCredentialsIfNeeded reports stale Keycloak sessions clearly", async () => {
+  globalThis.fetch = (async (input: RequestInfo | URL) => {
+    const url = String(input);
+    if (url.endsWith("/.well-known/openid-configuration")) {
+      return new Response(
+        JSON.stringify({
+          authorization_endpoint: "https://auth.example.test/auth",
+          token_endpoint: "https://auth.example.test/token",
+        }),
+        { status: 200, headers: { "content-type": "application/json" } },
+      );
+    }
+    return new Response(
+      JSON.stringify({
+        error: "invalid_grant",
+        error_description: "Session doesn't have required client",
+      }),
+      { status: 400, headers: { "content-type": "application/json" } },
+    );
+  }) as typeof fetch;
+
+  await saveCredentials({
+    apiUrl: "https://api.example.test",
+    token: "old-token",
+    refreshToken: "refresh-token",
+    expiresAt: 1,
+    email: "dev@example.test",
+    issuer: "https://auth.example.test",
+    clientId: "a2acloud-cli",
+  });
+
+  await assert.rejects(
+    refreshCredentialsIfNeeded((await loadCredentials())!),
+    /Login expired or revoked\. Run `a2amcp login` and retry\. .*Session doesn't have required client/,
+  );
+  assert.equal((await loadCredentials())!.token, "old-token");
+});