diff --git a/README.md b/README.md
index 1e149522..ea331484 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ We are using Pytest](https://docs.pytest.org/en/latest/index.html) for tests. Th
 
 To run the tests just execute:
 
-```
+```bash
 python3 -m pytest -v
 ```
 
diff --git a/requirements/dev.txt b/requirements/dev.txt
index e7f629d0..7c12fdab 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -5,7 +5,10 @@
 # For development
 
 # Tests
-pytest==4.1.1
+pytest==5.2.0
+
+# Mocking
+pytest-mock==2.0.0
 
 # Coverage
 coverage==4.5.1
\ No newline at end of file
diff --git a/tests/time_entries/time_enties_namespace_test.py b/tests/time_entries/time_enties_namespace_test.py
index 6d542456..b9efd63d 100644
--- a/tests/time_entries/time_enties_namespace_test.py
+++ b/tests/time_entries/time_enties_namespace_test.py
@@ -1,10 +1,14 @@
 from flask import json
 
-def test_list_should_return_empty_array(client):
+def test_list_should_return_empty_array(mocker, client):
+    from time_tracker_api.time_entries.time_entries_namespace import model
     """Should return an empty array"""
+    model_mock = mocker.patch.object(model, 'find_all', return_value=[])
+
     response = client.get("/time-entries", follow_redirects=True)
 
     assert 200 == response.status_code
 
     json_data = json.loads(response.data)
     assert [] == json_data
+    model_mock.assert_called_once()
diff --git a/time_tracker_api/__init__.py b/time_tracker_api/__init__.py
index c1a26a1a..a37e669c 100644
--- a/time_tracker_api/__init__.py
+++ b/time_tracker_api/__init__.py
@@ -1,8 +1,9 @@
 import os
+
 from flask import Flask
 
 
-def create_app(config_path='time_tracker_api.config.WhateverDevelopConfig',
+def create_app(config_path='time_tracker_api.config.DefaultConfig',
                config_data=None):
     flask_app = Flask(__name__)
 
@@ -12,7 +13,7 @@ def create_app(config_path='time_tracker_api.config.WhateverDevelopConfig',
     return flask_app
 
 
-def init_app_config(app, config_path, config_data=None):
+def init_app_config(app: Flask, config_path: str, config_data: dict = None):
     if config_path:
         app.config.from_object(config_path)
     else:
diff --git a/time_tracker_api/config.py b/time_tracker_api/config.py
index 7d6fab4b..8caec231 100644
--- a/time_tracker_api/config.py
+++ b/time_tracker_api/config.py
@@ -7,3 +7,6 @@ class WhateverDevelopConfig(Config):
     FLASK_DEBUG = True
     FLASK_ENV = "develop"
     DATABASE = "whatever"
+
+
+DefaultConfig = WhateverDevelopConfig
diff --git a/time_tracker_api/database.py b/time_tracker_api/database.py
index 45ec8093..80e297da 100644
--- a/time_tracker_api/database.py
+++ b/time_tracker_api/database.py
@@ -25,4 +25,4 @@ def create(model_name: str):
 
 def use_whatever():
     from time_tracker_api import whatever_repository
-    return whatever_repository
\ No newline at end of file
+    return whatever_repository