Firebase Stub: unit tests separated in different files

__mocks__/__tests__/gatsby-plugin-firebase/database.ref.once.test.js

@@ -0,0 +1,59 @@
+import FirebaseStub, { DatabaseConstants } from '../../gatsby-plugin-firebase';
+
+test('retrieves resume if it exists', async () => {
+  FirebaseStub.database().initializeData();
+
+  const resumeId = DatabaseConstants.demoStateResume1Id;
+
+  const resume = (
+    await FirebaseStub.database()
+      .ref(`${DatabaseConstants.resumesPath}/${resumeId}`)
+      .once('value')
+  ).val();
+
+  expect(resume).toBeTruthy();
+  expect(resume.id).toEqual(resumeId);
+});
+
+test('retrieves null if resume does not exist', async () => {
+  FirebaseStub.database().initializeData();
+
+  const resumeId = 'invalidResumeId';
+
+  const resume = (
+    await FirebaseStub.database()
+      .ref(`${DatabaseConstants.resumesPath}/${resumeId}`)
+      .once('value')
+  ).val();
+
+  expect(resume).toBeNull();
+});
+
+test('retrieves user if it exists', async () => {
+  FirebaseStub.database().initializeData();
+
+  const expectedUser = DatabaseConstants.user1;
+
+  const user = (
+    await FirebaseStub.database()
+      .ref(`${DatabaseConstants.usersPath}/${expectedUser.uid}`)
+      .once('value')
+  ).val();
+
+  expect(user).toBeTruthy();
+  expect(user).toEqual(expectedUser);
+});
+
+test('retrieves null if user does not exist', async () => {
+  FirebaseStub.database().initializeData();
+
+  const userId = 'invalidUserId';
+
+  const user = (
+    await FirebaseStub.database()
+      .ref(`${DatabaseConstants.usersPath}/${userId}`)
+      .once('value')
+  ).val();
+
+  expect(user).toBeNull();
+});