diff --git a/__mocks__/__tests__/gatsby-plugin-firebase_2.test.js b/__mocks__/__tests__/gatsby-plugin-firebase_2.test.js
new file mode 100644
index 00000000..febf78ad
--- /dev/null
+++ b/__mocks__/__tests__/gatsby-plugin-firebase_2.test.js
@@ -0,0 +1,45 @@
+import FirebaseMock from '../gatsby-plugin-firebase_2';
+
+describe('database', () => {
+  it('reuses existing Database instance', async () => {
+    const database1 = FirebaseMock.database();
+    const database2 = FirebaseMock.database();
+
+    expect(database1.uuid).toBeTruthy();
+    expect(database2.uuid).toBeTruthy();
+    expect(database1.uuid).toEqual(database2.uuid);
+  });
+
+  it('reuses existing Reference instance', async () => {
+    const ref1 = FirebaseMock.database().ref('resumes/123');
+    const ref2 = FirebaseMock.database().ref('resumes/123');
+
+    expect(ref1.uuid).toBeTruthy();
+    expect(ref2.uuid).toBeTruthy();
+    expect(ref1.uuid).toEqual(ref2.uuid);
+  });
+
+  it('ServerValue.TIMESTAMP returns current time in milliseconds', async () => {
+    const now = new Date().getTime();
+    const timestamp = FirebaseMock.database.ServerValue.TIMESTAMP;
+
+    expect(timestamp).toBeTruthy();
+    expect(timestamp).toBeGreaterThanOrEqual(now);
+  });
+
+  it("can spy on Reference 'update' function", async () => {
+    const referencePath = 'resumes/123456';
+    const functionSpy = jest.spyOn(
+      FirebaseMock.database().ref(referencePath),
+      'update',
+    );
+    const updateArgument = 'test value 123';
+
+    await FirebaseMock.database().ref(referencePath).update(updateArgument);
+
+    expect(functionSpy).toHaveBeenCalledTimes(1);
+    const functionCallArgument = functionSpy.mock.calls[0][0];
+    expect(functionCallArgument).toBeTruthy();
+    expect(functionCallArgument).toEqual(updateArgument);
+  });
+});
diff --git a/__mocks__/gatsby-plugin-firebase_2.js b/__mocks__/gatsby-plugin-firebase_2.js
new file mode 100644
index 00000000..f2b565b8
--- /dev/null
+++ b/__mocks__/gatsby-plugin-firebase_2.js
@@ -0,0 +1,215 @@
+import path from 'path';
+import fs from 'fs';
+import { v4 as uuidv4 } from 'uuid';
+
+class Reference {
+  #path = '';
+  #uuid = '';
+
+  constructor(path) {
+    if (typeof path === 'undefined' || path === null) {
+      this.#path = '.';
+    } else if (typeof path !== 'string') {
+      throw new Error('path should be a string.');
+    } else {
+      this.#path = path;
+    }
+
+    this.#uuid = uuidv4();
+  }
+
+  get path() {
+    return this.#path;
+  }
+
+  get uuid() {
+    return this.#uuid;
+  }
+
+  async update(value) {
+    return Promise.resolve(true);
+  }
+}
+
+class Database {
+  static testUser = {
+    email: 'test.user@noemail.com',
+    name: 'Test User',
+    uid: 'testuser123',
+  };
+  static #instance = undefined;
+  #uuid = '';
+  #data = {};
+  #references = {};
+
+  constructor() {
+    if (Database.#instance) {
+      return Database.#instance;
+    }
+
+    Database.#instance = this;
+
+    this.#uuid = uuidv4();
+  }
+
+  get demoResumeId() {
+    return 'demore';
+  }
+  get emptyResumeId() {
+    return 'mtre01';
+  }
+
+  get uuid() {
+    return this.#uuid;
+  }
+
+  initData() {
+    const resumes = {};
+    const demoResume = readFile('../src/data/demoState.json');
+    resumes[this.demoResumeId] = demoResume;
+    const emptyResume = readFile('../src/data/initialState.json');
+    resumes[this.emptyResumeId] = emptyResume;
+
+    for (var key in resumes) {
+      const resume = resumes[key];
+
+      resume.id = key;
+      resume.name = `Test Resume ${key}`;
+      resume.user = Database.testUser.uid;
+
+      let date = new Date('December 15, 2020 11:20:25');
+      resume.updatedAt = date.valueOf();
+      date.setMonth(date.getMonth() - 2);
+      resume.createdAt = date.valueOf();
+    }
+
+    this.#data['resumes'] = resumes;
+  }
+
+  readFile(fileRelativePath) {
+    const fileAbsolutePath = path.resolve(__dirname, fileRelativePath);
+    const fileBuffer = fs.readFileSync(fileAbsolutePath);
+    const fileData = JSON.parse(fileBuffer);
+    return fileData;
+  }
+
+  ref(path) {
+    const newRef = new Reference(path);
+    const existingRef = this.#references[newRef.path];
+    if (existingRef) {
+      return existingRef;
+    }
+
+    this.#references[newRef.path] = newRef;
+    return newRef;
+  }
+}
+
+/*
+const database = () => {
+  const ref = (path) => {
+    if (!path) {
+      throw new Error('Not implemented.');
+    }
+
+    const resumesPath = path.startsWith('resumes/');
+    const usersPath = path.startsWith('users/');
+    if (!resumesPath && !usersPath) {
+      throw new Error('Unknown Reference path.');
+    }
+
+    const databaseLocationId = path.substring(path.indexOf('/') + 1);
+    if (!databaseLocationId) {
+      throw new Error('Unknown database location id.');
+    }
+
+    const once = async (eventType) => {
+      if (!eventType) {
+        throw new Error('Event type must be provided.');
+      }
+
+      if (eventType !== 'value') {
+        throw new Error('Unknown event type.');
+      }
+
+      const val = () => {
+        if (resumesPath) {
+          return __resumesDictionary[databaseLocationId]
+            ? __resumesDictionary[databaseLocationId]
+            : null;
+        }
+
+        if (usersPath) {
+          return __testUser;
+        }
+
+        return null;
+      };
+
+      return Promise.resolve({ val });
+    };
+
+    const set = (value) => {
+      if (resumesPath) {
+        if (value === null) {
+          delete __resumesDictionary[databaseLocationId];
+        } else {
+          __resumesDictionary[databaseLocationId] = value;
+        }
+      }
+
+      return Promise.resolve(true);
+    };
+
+    const update = async (value) => {
+      if (resumesPath) {
+        if (value === null) {
+          delete __resumesDictionary[databaseLocationId];
+        } else {
+          __resumesDictionary[databaseLocationId] = value;
+        }
+      }
+
+      __databaseRefUpdateCalls.push(value);
+
+      return Promise.resolve(true);
+    };
+
+    return {
+      once,
+      set,
+      update,
+      __updateCalls: __databaseRefUpdateCalls,
+    };
+  };
+
+  return {
+    __demoResumeId,
+    __emptyResumeId,
+    __init,
+    ref,
+  };
+};
+
+database.ServerValue = {};
+Object.defineProperty(database.ServerValue, 'TIMESTAMP', {
+  get() {
+    return new Date().getTime();
+  },
+});
+*/
+
+class FirebaseMock {
+  static database() {
+    return new Database();
+  }
+}
+
+FirebaseMock.database.ServerValue = {};
+Object.defineProperty(FirebaseMock.database.ServerValue, 'TIMESTAMP', {
+  get() {
+    return new Date().getTime();
+  },
+});
+
+export default FirebaseMock;