1 files changed, 37 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/fake_date_spec.js b/spec/frontend/__helpers__/fake_date_spec.js
new file mode 100644
index 00000000000..b3ed13e238a
--- /dev/null
+++ b/spec/frontend/__helpers__/fake_date_spec.js
@@ -0,0 +1,37 @@
+import { createFakeDateClass, DEFAULT_ARGS, useRealDate } from './fake_date';
+
+describe('spec/helpers/fake_date', () => {
+  describe('createFakeDateClass', () => {
+    let FakeDate;
+
+    beforeAll(() => {
+      useRealDate();
+    });
+
+    beforeEach(() => {
+      FakeDate = createFakeDateClass(DEFAULT_ARGS);
+    });
+
+    it('should use default args', () => {
+      expect(new FakeDate()).toMatchInlineSnapshot(`2020-07-06T00:00:00.000Z`);
+    });
+
+    it('should use default args when called as a function', () => {
+      expect(FakeDate()).toMatchInlineSnapshot(
+        `"Mon Jul 06 2020 00:00:00 GMT+0000 (Greenwich Mean Time)"`,
+      );
+    });
+
+    it('should have deterministic now()', () => {
+      expect(FakeDate.now()).toMatchInlineSnapshot(`1593993600000`);
+    });
+
+    it('should be instanceof Date', () => {
+      expect(new FakeDate()).toBeInstanceOf(Date);
+    });
+
+    it('should be instanceof self', () => {
+      expect(new FakeDate()).toBeInstanceOf(FakeDate);
+    });
+  });
+});