Testing Tutorial

.gitignore

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+*.pyc
+__pycache__/
+.mypy_cache/

requirements.txt

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+appnope==0.1.0
+backcall==0.1.0
+decorator==4.4.0
+ipython==7.4.0
+ipython-genutils==0.2.0
+jedi==0.13.3
+nose==1.3.7
+parso==0.4.0
+pexpect==4.7.0
+pickleshare==0.7.5
+prompt-toolkit==2.0.9
+ptyprocess==0.6.0
+Pygments==2.3.1
+pymemcache==2.1.1
+redis==3.2.1
+six==1.12.0
+traitlets==4.3.2
+typed-ast==1.3.4
+wcwidth==0.1.7

setup.py

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+from setuptools import setup
+
+setup(
+    name='testingtutorials',
+    version='0.1dev',
+    packages=['testingtutorials'],
+    license=''
+)

testingtutorials/behaviortesting/prices.py

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+import json
+from abc import abstractmethod, ABC
+from typing import List
+
+from pymemcache.client.base import Client
+import redis
+
+
+class Memcache:
+    def __init__(self):
+        self._client = Client(('localhost', 11211))
+
+    def prices(self) -> List[float]:
+        """
+        Prices returns an array of all prices in the system.
+
+        :return:
+        """
+        # makes call to memcached...
+        return json.loads(self._client.get('prices'))
+
+
+class Redis:
+    def __init__(self):
+        self._client = redis.StrictRedis()
+
+    def prices(self) -> List[float]:
+        """
+        Prices returns an array of all prices in the system.
+
+        :return:
+        """
+        # makes call to redis...
+        return self._client.lrange('prices', 0, -1)
+
+
+class PriceAnalytics_Redis:
+    def __init__(self):
+        self.redis = Redis()
+
+    def avg_price(self) -> float:
+        prices = self.redis.prices()
+        return sum(prices) / float(len(prices))
+
+
+class PriceAnalytics_MigrateMemcache:
+    def __init__(self):
+        self.memcache = Memcache()
+
+    def avg_price(self) -> float:
+        prices = self.memcache.prices()
+        return sum(prices) / float(len(prices))
+
+
+class Datasource(ABC):
+    @abstractmethod
+    def prices(self) -> List[float]:
+        pass
+
+
+class PriceAnalyticsEvolvable:
+    def __init__(self, datasource: Datasource):
+        self.datasource = datasource
+
+    def avg_price(self) -> float:
+        prices = self.datasource.prices()
+        return sum(prices) / float(len(prices))
+

tests/behaviortesting/test_prices.py

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+import unittest
+from unittest.mock import patch, MagicMock
+from testingtutorials.behaviortesting.prices import PriceAnalytics_Redis, PriceAnalyticsEvolvable, \
+    PriceAnalytics_MigrateMemcache
+
+
+class PriceAnalytics_Redis_TestCase(unittest.TestCase):
+
+    @patch('testingtutorials.behaviortesting.prices.Redis')
+    def test_avg_price_success(self, mock_redis):
+        redis_instance = mock_redis.return_value
+        redis_instance.prices.return_value = [1, 1]
+
+        analytics = PriceAnalytics_Redis()
+
+        self.assertEqual(
+            1,
+            analytics.avg_price(),
+        )
+
+        redis_instance.prices.assert_called_once()
+
+
+class PriceAnalytics_MigrateMemcache_TestCase(unittest.TestCase):
+
+    @patch('testingtutorials.behaviortesting.prices.Redis')
+    def test_avg_price_success(self, mock_redis):
+        redis_instance = mock_redis.return_value
+        redis_instance.prices.return_value = [1, 1]
+
+        analytics = PriceAnalytics_MigrateMemcache()
+
+        self.assertEqual(
+            1,
+            analytics.avg_price(),
+        )
+
+        redis_instance.prices.assert_called_once()
+
+
+class PriceAnalyticsEvolvableTestCase(unittest.TestCase):
+
+    def test_avg_price_success(self):
+        ds = MagicMock(
+            prices=MagicMock(
+                return_value=[1, 1]
+            )
+        )
+
+        analytics = PriceAnalyticsEvolvable(
+            datasource=ds
+        )
+
+        self.assertEqual(
+            1,
+            analytics.avg_price(),
+        )