tests/cpydiff: Add os module environ differences.

tests/cpydiff/modules_os_environ.py

@@ -0,0 +1,16 @@
+"""
+categories: Modules,os
+description: ``environ`` attribute is not implemented
+cause: Unknown
+workaround: Use ``getenv``, ``putenv`` and ``unsetenv``
+"""
+import os
+try:
+    print(os.environ.get('NEW_VARIABLE'))
+    os.environ['NEW_VARIABLE'] = 'VALUE'
+    print(os.environ['NEW_VARIABLE'])
+except AttributeError:
+    print('should not get here')
+    print(os.getenv('NEW_VARIABLE'))
+    os.putenv('NEW_VARIABLE', 'VALUE')
+    print(os.getenv('NEW_VARIABLE'))

tests/cpydiff/modules_os_getenv.py

@@ -0,0 +1,10 @@
+"""
+categories: Modules,os
+description: ``getenv`` returns actual value instead of cached value
+cause: The ``environ`` attribute is not implemented
+workaround: Unknown
+"""
+import os
+print(os.getenv('NEW_VARIABLE'))
+os.putenv('NEW_VARIABLE', 'VALUE')
+print(os.getenv('NEW_VARIABLE'))

tests/cpydiff/modules_os_getenv_argcount.py

@@ -0,0 +1,13 @@
+"""
+categories: Modules,os
+description: ``getenv`` only allows one argument
+cause: Unknown
+workaround: Test that the return value is ``None``
+"""
+import os
+try:
+    print(os.getenv('NEW_VARIABLE', 'DEFAULT'))
+except TypeError:
+    print('should not get here')
+    # this assumes NEW_VARIABLE is never an empty variable
+    print(os.getenv('NEW_VARIABLE') or 'DEFAULT')