diff --git a/part4/bloglist/app.js b/part4/bloglist/app.js
index df2d810..5b13529 100644
--- a/part4/bloglist/app.js
+++ b/part4/bloglist/app.js
@@ -1,5 +1,6 @@
 const config = require('./utils/config')
 const express = require('express')
+require('express-async-errors')
 const app = express()
 const cors = require('cors')
 const blogsRouter = require('./controllers/blogs')
diff --git a/part4/bloglist/controllers/blogs.js b/part4/bloglist/controllers/blogs.js
index d72edbc..f8748e7 100644
--- a/part4/bloglist/controllers/blogs.js
+++ b/part4/bloglist/controllers/blogs.js
@@ -1,24 +1,23 @@
 const blogsRouter = require('express').Router()
 const Blog = require('../models/blog')
 
-blogsRouter.get('/', (request, response, next) => {
-  Blog
-    .find({})
-    .then(blogs => {
-      response.json(blogs)
-    })
-    .catch(error => next(error))
+blogsRouter.get('/', async (request, response) => {
+  const blogs = await Blog.find({})
+  response.json(blogs)
 })
 
-blogsRouter.post('/', (request, response, next) => {
-  const blog = new Blog(request.body)
-  console.log(request.body)
-  blog
-    .save()
-    .then(result => {
-      response.status(201).json(result)
-    })
-    .catch(error => next(error))
+blogsRouter.post('/', async (request, response) => {
+  const body = request.body
+
+  const blog = await (new Blog({
+    title: body.title,
+    author: body.author,
+    url: body.url,
+    likes: body.likes
+  })).save()
+
+  response.status(201).json(blog)
+
 })
 
 module.exports = blogsRouter
\ No newline at end of file
diff --git a/part4/bloglist/models/blog.js b/part4/bloglist/models/blog.js
index fecc149..811c03c 100644
--- a/part4/bloglist/models/blog.js
+++ b/part4/bloglist/models/blog.js
@@ -1,10 +1,22 @@
 const mongoose = require('mongoose')
 
 const blogSchema = new mongoose.Schema({
-  title: String,
-  author: String,
-  url: String,
-  likes: Number
+  title: {
+    type: String,
+    required: true
+  },
+  author: {
+    type: String,
+    required: true
+  },
+  url: {
+    type: String,
+    required: true
+  },
+  likes: {
+    type: Number,
+    required: true
+  }
 })
 
 blogSchema.set('toJSON', {
diff --git a/part4/bloglist/package-lock.json b/part4/bloglist/package-lock.json
index 8d596a1..370118c 100644
--- a/part4/bloglist/package-lock.json
+++ b/part4/bloglist/package-lock.json
@@ -13,6 +13,7 @@
         "cross-env": "^7.0.3",
         "dotenv": "^16.1.1",
         "express": "^4.18.2",
+        "express-async-errors": "^3.1.1",
         "mongoose": "^7.2.2"
       },
       "devDependencies": {
@@ -2430,6 +2431,14 @@
         "node": ">= 0.10.0"
       }
     },
+    "node_modules/express-async-errors": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/express-async-errors/-/express-async-errors-3.1.1.tgz",
+      "integrity": "sha512-h6aK1da4tpqWSbyCa3FxB/V6Ehd4EEB15zyQq9qe75OZBp0krinNKuH4rAY+S/U/2I36vdLAUFSjQJ+TFmODng==",
+      "peerDependencies": {
+        "express": "^4.16.2"
+      }
+    },
     "node_modules/express/node_modules/debug": {
       "version": "2.6.9",
       "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.9.tgz",
diff --git a/part4/bloglist/package.json b/part4/bloglist/package.json
index c818d95..b0dbe18 100644
--- a/part4/bloglist/package.json
+++ b/part4/bloglist/package.json
@@ -15,6 +15,7 @@
     "cross-env": "^7.0.3",
     "dotenv": "^16.1.1",
     "express": "^4.18.2",
+    "express-async-errors": "^3.1.1",
     "mongoose": "^7.2.2"
   },
   "devDependencies": {
diff --git a/part4/bloglist/tests/blog_api.test.js b/part4/bloglist/tests/blog_api.test.js
index 65fd55e..712a7d5 100644
--- a/part4/bloglist/tests/blog_api.test.js
+++ b/part4/bloglist/tests/blog_api.test.js
@@ -4,6 +4,14 @@ const app = require('../app')
 
 const api = supertest(app)
 
+const Blog = require('../models/blog')
+const helper = require('./test_helper')
+
+beforeEach(async () => {
+  await Blog.deleteMany({})
+  await Blog.insertMany(helper.initialBlogs)
+})
+
 test('blogs are returned as json', async () => {
   await api
     .get('/api/blogs')
@@ -11,6 +19,48 @@ test('blogs are returned as json', async () => {
     .expect('Content-Type', /application\/json/)
 })
 
+test('all blogs are returned', async () => {
+  const response = await api.get('/api/blogs')
+  expect(response.body).toHaveLength(helper.initialBlogs.length)
+})
+
+test('a specific blog is within the returned blogs', async () => {
+  const response = await api.get('/api/blogs')
+  const contents = response.body.map((r) => r.title)
+  expect(contents).toContain('Another blog')
+})
+
+test('a valid blog can be added ', async () => {
+  const newBlog = {
+    title: 'Test',
+    author: 'Tester',
+    url: 'http:/test.com',
+    likes: 999
+  }
+
+  await api
+    .post('/api/blogs')
+    .send(newBlog)
+    .expect(201)
+    .expect('Content-Type', /application\/json/)
+
+  const blogsAtEnd = await helper.blogsInDb()
+  expect(blogsAtEnd).toHaveLength(helper.initialBlogs.length + 1)
+  const contents = blogsAtEnd.map((n) => n.title)
+  expect(contents).toContain('Test')
+})
+
+test('blog without content is not added', async () => {
+  const newBlog = {
+    likes: 999
+  }
+
+  await api.post('/api/blogs').send(newBlog).expect(400)
+
+  const blogsAtEnd = await helper.blogsInDb()
+  expect(blogsAtEnd).toHaveLength(helper.initialBlogs.length)
+})
+
 afterAll(async () => {
   await mongoose.connection.close()
-})
\ No newline at end of file
+})
diff --git a/part4/bloglist/tests/test_helper.js b/part4/bloglist/tests/test_helper.js
new file mode 100644
index 0000000..6e082a2
--- /dev/null
+++ b/part4/bloglist/tests/test_helper.js
@@ -0,0 +1,45 @@
+const Blog = require('../models/blog')
+
+const initialBlogs = [
+  {
+    title: 'My blog',
+    author: 'Andrew',
+    url: 'www.andrew.eu',
+    likes: 1000,
+  },
+  {
+    title: 'My blog 2',
+    author: 'Andrew',
+    url: 'www.andrew.eu',
+    likes: 3000,
+  },
+  {
+    title: 'Another blog',
+    author: 'Hans',
+    url: 'www.andrew.eu',
+    likes: 5000,
+  }
+]
+
+const nonExistingId = async () => {
+  const blog = new Blog({
+    title: 'Test',
+    author: 'tester',
+    url: 'www.test.eu',
+    likes: 999,
+  })
+
+  await blog.save()
+  await blog.deleteOne()
+
+  return blog._id.toString()
+}
+
+const blogsInDb = async () => {
+  const blogs = await Blog.find({})
+  return blogs.map(blog => blog.toJSON())
+}
+
+module.exports = {
+  initialBlogs, nonExistingId, blogsInDb
+}
\ No newline at end of file
diff --git a/part4/bloglist/utils/config.js b/part4/bloglist/utils/config.js
index 979b2c7..807c7e3 100644
--- a/part4/bloglist/utils/config.js
+++ b/part4/bloglist/utils/config.js
@@ -1,7 +1,9 @@
 require('dotenv').config()
 
 const PORT = process.env.PORT
-const MONGODB_URI = process.env.MONGODB_URI
+const MONGODB_URI = process.env.NODE_ENV === 'test'
+  ? process.env.TEST_MONGODB_URI
+  : process.env.MONGODB_URI
 
 module.exports = {
   MONGODB_URI,
diff --git a/part4/bloglist/utils/logger.js b/part4/bloglist/utils/logger.js
index 3c55ba7..2fe10f5 100644
--- a/part4/bloglist/utils/logger.js
+++ b/part4/bloglist/utils/logger.js
@@ -1,9 +1,13 @@
 const info = (...params) => {
-  console.log(...params)
+  if (process.env.NODE_ENV !== 'test') {
+    console.log(...params)
+  }
 }
 
 const error = (...params) => {
-  console.error(...params)
+  if (process.env.NODE_ENV !== 'test') {
+    console.error(...params)
+  }
 }
 
 module.exports = {