Merge branch 'fkromer-parameter_injection'

faif · faif · commit b14a65472274 · 2017-04-23T22:48:41.000+02:00
diff --git a/README.md b/README.md
@@ -56,6 +56,13 @@ __Behavioral Patterns__:
 | [template](behavioral/template.py) | an object imposes a structure but takes pluggable components |
 | [visitor](behavioral/visitor.py) | invoke a callback for all items of a collection |
 
+__Design for Testability Patterns__:
+
+| Pattern | Description |
+|:-------:| ----------- |
+| [constructor_injection](dft/constructor_injection.py) | the client provides the depended-on object to the SUT via the class construtor (implmentation variant of dependency injection) |
+| [parameter_injection](dft/parameter_injection.py) | the client provides the depended-on object to the SUT via a parameter(implmentation variant of dependency injection) |
+
 __Fundamental Patterns__:
 
 | Pattern | Description |
diff --git a/dft/parameter_injection.py b/dft/parameter_injection.py
@@ -3,7 +3,7 @@
 import datetime
 
 """
-Port of the Java example of "Constructor Injection" in
+Port of the Java example of "Parameter Injection" in
 "xUnit Test Patterns - Refactoring Test Code" by Gerard Meszaros
 (ISBN-10: 0131495054, ISBN-13: 978-0131495050) accessible in outdated version on
 http://xunitpatterns.com/Dependency%20Injection.html.
@@ -23,11 +23,11 @@ def get_current_time_as_html_fragment(self):
 
 class TimeDisplay(object):
 
-    def __init__(self, time_provider):
-        self.time_provider = time_provider
+    def __init__(self):
+        pass
 
-    def get_current_time_as_html_fragment(self):
-        current_time = self.time_provider.now()
+    def get_current_time_as_html_fragment(self, time_provider):
+        current_time = time_provider.now()
         current_time_as_html_fragment = "<span class=\"tinyBoldText\">" + current_time + "</span>"
         return current_time_as_html_fragment
 
diff --git a/tests/test_parameter_injection.py b/tests/test_parameter_injection.py
@@ -2,10 +2,10 @@
 # -*- coding: utf-8 -*-
 import unittest
 
-from dft.constructor_injection import TimeDisplay, MidnightTimeProvider, ProductionCodeTimeProvider, datetime
+from dft.parameter_injection import TimeDisplay, MidnightTimeProvider, ProductionCodeTimeProvider, datetime
 
 """
-Port of the Java example of "Constructor Injection" in
+Port of the Java example of "Parameter Injection" in
 "xUnit Test Patterns - Refactoring Test Code" by Gerard Meszaros
 (ISBN-10: 0131495054, ISBN-13: 978-0131495050) accessible in outdated version on
 http://xunitpatterns.com/Dependency%20Injection.html.
@@ -20,28 +20,25 @@ def test_display_current_time_at_midnight(self):
         self.assertEqual(result, expected_time)
 """
 
-class ConstructorInjectionTest(unittest.TestCase):
+class ParameterInjectionTest(unittest.TestCase):
 
     def test_display_current_time_at_midnight(self):
         """
         Would almost always fail (despite of right at/after midnight) if
         untestable production code would have been used.
         """
         time_provider_stub = MidnightTimeProvider()
-        class_under_test = TimeDisplay(time_provider_stub)
+        class_under_test = TimeDisplay()
         expected_time = "<span class=\"tinyBoldText\">24:01</span>"
-        self.assertEqual(class_under_test.get_current_time_as_html_fragment(), expected_time)
+        self.assertEqual(class_under_test.get_current_time_as_html_fragment(time_provider_stub), expected_time)
 
     def test_display_current_time_at_current_time(self):
         """
         Just as justification for working example with the time provider used in
         production. (Will always pass.)
         """
         production_code_time_provider = ProductionCodeTimeProvider()
-        class_under_test = TimeDisplay(production_code_time_provider)
+        class_under_test = TimeDisplay()
         current_time = datetime.datetime.now()
         expected_time = "<span class=\"tinyBoldText\">{}:{}</span>".format(current_time.hour, current_time.minute)
-        self.assertEqual(class_under_test.get_current_time_as_html_fragment(), expected_time)
-
-if __name__ == "__main__":
-    unittest.main()
+        self.assertEqual(class_under_test.get_current_time_as_html_fragment(production_code_time_provider), expected_time)
