1 files changed, 41 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/fake_date/jest.js b/spec/frontend/__helpers__/fake_date/jest.js
new file mode 100644
index 00000000000..65e45619049
--- /dev/null
+++ b/spec/frontend/__helpers__/fake_date/jest.js
@@ -0,0 +1,41 @@
+import { createJestExecutionWatcher } from '../jest_execution_watcher';
+import { RealDate, createFakeDateClass } from './fake_date';
+
+const throwInsideExecutionError = (fnName) => {
+  throw new Error(`Cannot call "${fnName}" during test execution (i.e. within "it", "beforeEach", "beforeAll", etc.).
+
+Instead, please move the call to "${fnName}" inside the "describe" block itself.
+
+      describe('', () => {
+    +   ${fnName}();
+
+        it('', () => {
+    -     ${fnName}();
+        })
+      })
+`);
+};
+
+const isExecutingTest = createJestExecutionWatcher();
+
+export const useDateInScope = (fnName, factory) => {
+  if (isExecutingTest()) {
+    throwInsideExecutionError(fnName);
+  }
+
+  let origDate;
+
+  beforeAll(() => {
+    origDate = global.Date;
+    global.Date = factory();
+  });
+
+  afterAll(() => {
+    global.Date = origDate;
+  });
+};
+
+export const useFakeDate = (...args) =>
+  useDateInScope('useFakeDate', () => createFakeDateClass(args));
+
+export const useRealDate = () => useDateInScope('useRealDate', () => RealDate);