diff --git a/actions/setup/js/check_stop_time.cjs b/actions/setup/js/check_stop_time.cjs
index 4e86da0f8a..96dff917c9 100644
--- a/actions/setup/js/check_stop_time.cjs
+++ b/actions/setup/js/check_stop_time.cjs
@@ -1,9 +1,21 @@
 // @ts-check
 /// <reference types="@actions/github-script" />
 
+/**
+ * Validates date format and returns true if valid
+ * @param {Date} date - Date to validate
+ * @returns {boolean} True if date is valid
+ */
+function isValidDate(date) {
+  return !isNaN(date.getTime());
+}
+
+/**
+ * Checks if workflow execution should stop based on configured stop time
+ * @returns {Promise<void>}
+ */
 async function main() {
-  const stopTime = process.env.GH_AW_STOP_TIME;
-  const workflowName = process.env.GH_AW_WORKFLOW_NAME;
+  const { GH_AW_STOP_TIME: stopTime, GH_AW_WORKFLOW_NAME: workflowName } = process.env;
 
   if (!stopTime) {
     core.setFailed("Configuration error: GH_AW_STOP_TIME not specified.");
@@ -17,10 +29,9 @@ async function main() {
 
   core.info(`Checking stop-time limit: ${stopTime}`);
 
-  // Parse the stop time (format: "YYYY-MM-DD HH:MM:SS")
   const stopTimeDate = new Date(stopTime);
 
-  if (isNaN(stopTimeDate.getTime())) {
+  if (!isValidDate(stopTimeDate)) {
     core.setFailed(`Invalid stop-time format: ${stopTime}. Expected format: YYYY-MM-DD HH:MM:SS`);
     return;
   }
diff --git a/actions/setup/js/check_stop_time.test.cjs b/actions/setup/js/check_stop_time.test.cjs
index bfa82031f4..074c833aca 100644
--- a/actions/setup/js/check_stop_time.test.cjs
+++ b/actions/setup/js/check_stop_time.test.cjs
@@ -1,101 +1,141 @@
 import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
 import fs from "fs";
 import path from "path";
+
 const mockCore = {
-    debug: vi.fn(),
-    info: vi.fn(),
-    notice: vi.fn(),
-    warning: vi.fn(),
-    error: vi.fn(),
-    setFailed: vi.fn(),
-    setOutput: vi.fn(),
-    exportVariable: vi.fn(),
-    setSecret: vi.fn(),
-    setCancelled: vi.fn(),
-    setError: vi.fn(),
-    getInput: vi.fn(),
-    getBooleanInput: vi.fn(),
-    getMultilineInput: vi.fn(),
-    getState: vi.fn(),
-    saveState: vi.fn(),
-    startGroup: vi.fn(),
-    endGroup: vi.fn(),
-    group: vi.fn(),
-    addPath: vi.fn(),
-    setCommandEcho: vi.fn(),
-    isDebug: vi.fn().mockReturnValue(!1),
-    getIDToken: vi.fn(),
-    toPlatformPath: vi.fn(),
-    toPosixPath: vi.fn(),
-    toWin32Path: vi.fn(),
-    summary: { addRaw: vi.fn().mockReturnThis(), write: vi.fn().mockResolvedValue() },
-  },
-  mockGithub = { rest: { actions: { listRepoWorkflows: vi.fn(), disableWorkflow: vi.fn() } } },
-  mockContext = { repo: { owner: "testowner", repo: "testrepo" } };
-((global.core = mockCore),
-  (global.github = mockGithub),
-  (global.context = mockContext),
-  describe("check_stop_time.cjs", () => {
-    let checkStopTimeScript, originalEnv;
-    (beforeEach(() => {
-      (vi.clearAllMocks(), (originalEnv = { GH_AW_STOP_TIME: process.env.GH_AW_STOP_TIME, GH_AW_WORKFLOW_NAME: process.env.GH_AW_WORKFLOW_NAME }));
-      const scriptPath = path.join(process.cwd(), "check_stop_time.cjs");
-      checkStopTimeScript = fs.readFileSync(scriptPath, "utf8");
-    }),
-      afterEach(() => {
-        (void 0 !== originalEnv.GH_AW_STOP_TIME ? (process.env.GH_AW_STOP_TIME = originalEnv.GH_AW_STOP_TIME) : delete process.env.GH_AW_STOP_TIME,
-          void 0 !== originalEnv.GH_AW_WORKFLOW_NAME ? (process.env.GH_AW_WORKFLOW_NAME = originalEnv.GH_AW_WORKFLOW_NAME) : delete process.env.GH_AW_WORKFLOW_NAME);
-      }),
-      describe("when stop time is not configured", () => {
-        (it("should fail if GH_AW_STOP_TIME is not set", async () => {
-          (delete process.env.GH_AW_STOP_TIME,
-            (process.env.GH_AW_WORKFLOW_NAME = "test-workflow"),
-            await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`),
-            expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("GH_AW_STOP_TIME not specified")),
-            expect(mockCore.setOutput).not.toHaveBeenCalled());
-        }),
-          it("should fail if GH_AW_WORKFLOW_NAME is not set", async () => {
-            ((process.env.GH_AW_STOP_TIME = "2025-12-31 23:59:59"),
-              delete process.env.GH_AW_WORKFLOW_NAME,
-              await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`),
-              expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("GH_AW_WORKFLOW_NAME not specified")),
-              expect(mockCore.setOutput).not.toHaveBeenCalled());
-          }));
-      }),
-      describe("when stop time format is invalid", () => {
-        it("should fail with error for invalid format", async () => {
-          ((process.env.GH_AW_STOP_TIME = "invalid-date"),
-            (process.env.GH_AW_WORKFLOW_NAME = "test-workflow"),
-            await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`),
-            expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("Invalid stop-time format")),
-            expect(mockCore.setOutput).not.toHaveBeenCalled());
-        });
-      }),
-      describe("when stop time is in the future", () => {
-        it("should allow execution", async () => {
-          const futureDate = new Date();
-          futureDate.setFullYear(futureDate.getFullYear() + 1);
-          const stopTime = futureDate.toISOString().replace("T", " ").substring(0, 19);
-          ((process.env.GH_AW_STOP_TIME = stopTime),
-            (process.env.GH_AW_WORKFLOW_NAME = "test-workflow"),
-            await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`),
-            expect(mockCore.setOutput).toHaveBeenCalledWith("stop_time_ok", "true"),
-            expect(mockCore.setFailed).not.toHaveBeenCalled());
-        });
-      }),
-      describe("when stop time has been reached", () => {
-        it("should set stop_time_ok to false without attempting to disable workflow", async () => {
-          const pastDate = new Date();
-          pastDate.setFullYear(pastDate.getFullYear() - 1);
-          const stopTime = pastDate.toISOString().replace("T", " ").substring(0, 19);
-          ((process.env.GH_AW_STOP_TIME = stopTime),
-            (process.env.GH_AW_WORKFLOW_NAME = "test-workflow"),
-            await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`),
-            expect(mockCore.warning).toHaveBeenCalledWith(expect.stringContaining("Stop time reached")),
-            expect(mockGithub.rest.actions.listRepoWorkflows).not.toHaveBeenCalled(),
-            expect(mockGithub.rest.actions.disableWorkflow).not.toHaveBeenCalled(),
-            expect(mockCore.setOutput).toHaveBeenCalledWith("stop_time_ok", "false"),
-            expect(mockCore.setFailed).not.toHaveBeenCalled());
-        });
-      }));
-  }));
+  debug: vi.fn(),
+  info: vi.fn(),
+  notice: vi.fn(),
+  warning: vi.fn(),
+  error: vi.fn(),
+  setFailed: vi.fn(),
+  setOutput: vi.fn(),
+  exportVariable: vi.fn(),
+  setSecret: vi.fn(),
+  setCancelled: vi.fn(),
+  setError: vi.fn(),
+  getInput: vi.fn(),
+  getBooleanInput: vi.fn(),
+  getMultilineInput: vi.fn(),
+  getState: vi.fn(),
+  saveState: vi.fn(),
+  startGroup: vi.fn(),
+  endGroup: vi.fn(),
+  group: vi.fn(),
+  addPath: vi.fn(),
+  setCommandEcho: vi.fn(),
+  isDebug: vi.fn().mockReturnValue(false),
+  getIDToken: vi.fn(),
+  toPlatformPath: vi.fn(),
+  toPosixPath: vi.fn(),
+  toWin32Path: vi.fn(),
+  summary: { addRaw: vi.fn().mockReturnThis(), write: vi.fn().mockResolvedValue() },
+};
+
+const mockGithub = {
+  rest: { actions: { listRepoWorkflows: vi.fn(), disableWorkflow: vi.fn() } },
+};
+
+const mockContext = { repo: { owner: "testowner", repo: "testrepo" } };
+
+global.core = mockCore;
+global.github = mockGithub;
+global.context = mockContext;
+
+describe("check_stop_time.cjs", () => {
+  let checkStopTimeScript;
+  let originalEnv;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    originalEnv = {
+      GH_AW_STOP_TIME: process.env.GH_AW_STOP_TIME,
+      GH_AW_WORKFLOW_NAME: process.env.GH_AW_WORKFLOW_NAME,
+    };
+    const scriptPath = path.join(process.cwd(), "check_stop_time.cjs");
+    checkStopTimeScript = fs.readFileSync(scriptPath, "utf8");
+  });
+
+  afterEach(() => {
+    if (originalEnv.GH_AW_STOP_TIME !== undefined) {
+      process.env.GH_AW_STOP_TIME = originalEnv.GH_AW_STOP_TIME;
+    } else {
+      delete process.env.GH_AW_STOP_TIME;
+    }
+
+    if (originalEnv.GH_AW_WORKFLOW_NAME !== undefined) {
+      process.env.GH_AW_WORKFLOW_NAME = originalEnv.GH_AW_WORKFLOW_NAME;
+    } else {
+      delete process.env.GH_AW_WORKFLOW_NAME;
+    }
+  });
+
+  describe("when stop time is not configured", () => {
+    it("should fail if GH_AW_STOP_TIME is not set", async () => {
+      delete process.env.GH_AW_STOP_TIME;
+      process.env.GH_AW_WORKFLOW_NAME = "test-workflow";
+
+      await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`);
+
+      expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("GH_AW_STOP_TIME not specified"));
+      expect(mockCore.setOutput).not.toHaveBeenCalled();
+    });
+
+    it("should fail if GH_AW_WORKFLOW_NAME is not set", async () => {
+      process.env.GH_AW_STOP_TIME = "2025-12-31 23:59:59";
+      delete process.env.GH_AW_WORKFLOW_NAME;
+
+      await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`);
+
+      expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("GH_AW_WORKFLOW_NAME not specified"));
+      expect(mockCore.setOutput).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("when stop time format is invalid", () => {
+    it("should fail with error for invalid format", async () => {
+      process.env.GH_AW_STOP_TIME = "invalid-date";
+      process.env.GH_AW_WORKFLOW_NAME = "test-workflow";
+
+      await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`);
+
+      expect(mockCore.setFailed).toHaveBeenCalledWith(expect.stringContaining("Invalid stop-time format"));
+      expect(mockCore.setOutput).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("when stop time is in the future", () => {
+    it("should allow execution", async () => {
+      const futureDate = new Date();
+      futureDate.setFullYear(futureDate.getFullYear() + 1);
+      const stopTime = futureDate.toISOString().replace("T", " ").substring(0, 19);
+
+      process.env.GH_AW_STOP_TIME = stopTime;
+      process.env.GH_AW_WORKFLOW_NAME = "test-workflow";
+
+      await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`);
+
+      expect(mockCore.setOutput).toHaveBeenCalledWith("stop_time_ok", "true");
+      expect(mockCore.setFailed).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("when stop time has been reached", () => {
+    it("should set stop_time_ok to false without attempting to disable workflow", async () => {
+      const pastDate = new Date();
+      pastDate.setFullYear(pastDate.getFullYear() - 1);
+      const stopTime = pastDate.toISOString().replace("T", " ").substring(0, 19);
+
+      process.env.GH_AW_STOP_TIME = stopTime;
+      process.env.GH_AW_WORKFLOW_NAME = "test-workflow";
+
+      await eval(`(async () => { ${checkStopTimeScript}; await main(); })()`);
+
+      expect(mockCore.warning).toHaveBeenCalledWith(expect.stringContaining("Stop time reached"));
+      expect(mockGithub.rest.actions.listRepoWorkflows).not.toHaveBeenCalled();
+      expect(mockGithub.rest.actions.disableWorkflow).not.toHaveBeenCalled();
+      expect(mockCore.setOutput).toHaveBeenCalledWith("stop_time_ok", "false");
+      expect(mockCore.setFailed).not.toHaveBeenCalled();
+    });
+  });
+});