diff --git a/index.test.js b/index.test.js
index f2f2f14..d62d4dd 100644
--- a/index.test.js
+++ b/index.test.js
@@ -1,17 +1,17 @@
 const test = require('ava')
 const sinon = require('sinon')
-const db = require('./lib/db')
+const { UsersCollection } = require('./lib/db')
 
 const userRepository = require('./lib/user-repository')
 const emailService = require('./lib/email-service')
 const newsletter = require('.')
 
 test.beforeEach(async () => {
-  await db.get('users').remove({})
+  await UsersCollection.remove({})
 })
 
 test('sends a newsletter to users that did not yet receive it', async t => {
-  await db.get('users').insert({ name: 'test', email: 'test@test.com', lastEmailSentAt: null })
+  await UsersCollection.insert({ name: 'test', email: 'test@test.com', lastEmailSentAt: null })
 
   sinon.spy(userRepository, 'findNotYetReceivedNewsletter')
   sinon.stub(emailService, 'sendTo')
diff --git a/lib/db.js b/lib/db.js
index d2d5f84..c61282d 100644
--- a/lib/db.js
+++ b/lib/db.js
@@ -1,4 +1,6 @@
 const monk = require('monk')
 const db = monk(process.env.MONGO_URL)
 
-module.exports = db
+module.exports = {
+  UsersCollection: db.get('users')
+}
diff --git a/lib/user-repository.js b/lib/user-repository.js
index 23d4663..e320ff9 100644
--- a/lib/user-repository.js
+++ b/lib/user-repository.js
@@ -1,8 +1,8 @@
-const db = require('./db')
+const { UsersCollection } = require('./db')
 
 module.exports = {
   findNotYetReceivedNewsletter: () => {
-    return db.get('users').find({
+    return UsersCollection.find({
       lastEmailSentAt: null
     })
   }
diff --git a/lib/user-repository.test.js b/lib/user-repository.test.js
index c1c5b2b..094b063 100644
--- a/lib/user-repository.test.js
+++ b/lib/user-repository.test.js
@@ -1,15 +1,21 @@
 const test = require('ava')
-const db = require('./db')
+const sinon = require('sinon')
 const userRepository = require('./user-repository')
+const { UsersCollection } = require('./db')
 
 test.beforeEach(async () => {
-  await db.get('users').remove({})
+  await UsersCollection.remove({})
 })
 
 test('find users that did not yet receive the newsletter', async t => {
-  await db.get('users').insert({ name: 'test', email: 'test@test.com', lastEmailSentAt: null })
+  await UsersCollection.insert({ name: 'test', email: 'test@test.com', lastEmailSentAt: null })
+
+  sinon.spy(UsersCollection, 'find')
 
   const users = await userRepository.findNotYetReceivedNewsletter()
   t.true(Array.isArray(users))
   t.is(users.length, 1)
+
+  t.true(UsersCollection.find.calledOnce)
+  t.true(UsersCollection.find.calledWith({ lastEmailSentAt: null }))
 })