docstring: Add decorator to format the docstrings

Some test frameworks like nose use the docstring to output information
about a test. In the case of generated tests all of them would get the
same description. Add a decorator which allows formating of the
docstring for each generated test function using the test values.

Example:

@DaTa(1,2)
@format_doc
def test_A(value):
    """Test A for value {}"""
    ...

executed with "nosetests -v", will output:
Test A for value 1
Test A for value 2

Signed-off-by: [email protected]

ddt.py

@@ -21,6 +21,7 @@
 DATA_ATTR = '%values'      # store the data the test must run with
 FILE_ATTR = '%file_path'   # store the path to JSON file
 UNPACK_ATTR = '%unpack'    # remember that we have to unpack values
+DOC_ATTR = '%doc'          # remember that we have to format the docstring
 
 
 def unpack(func):
@@ -32,6 +33,15 @@ def unpack(func):
     return func
 
 
+def format_doc(func):
+    """
+    Method decorator to add value formating to the decorated functions
+
+    """
+    setattr(func, DOC_ATTR, True)
+    return func
+
+
 def data(*values):
     """
     Method decorator to add to your test methods.
@@ -145,6 +155,8 @@ def feed_data(func, new_name, *args, **kwargs):
     def wrapper(self):
         return func(self, *args, **kwargs)
     wrapper.__name__ = new_name
+    if hasattr(func, DOC_ATTR):
+        wrapper.__doc__ = func.__doc__.format(*args, **kwargs)
     return wrapper
 
 

test/test_example.py

@@ -1,5 +1,5 @@
 import unittest
-from ddt import ddt, data, file_data, unpack
+from ddt import ddt, data, file_data, unpack, format_doc
 from test.mycode import larger_than_two, has_three_elements, is_a_greeting
 
 
@@ -58,3 +58,16 @@ def test_dicts_extracted_into_kwargs(self, first, second, third):
     @data(u'ascii', u'non-ascii-\N{SNOWMAN}')
     def test_unicode(self, value):
         self.assertIn(value, (u'ascii', u'non-ascii-\N{SNOWMAN}'))
+
+    @format_doc
+    @data(3, 4, 12, 23)
+    def test_larger_than_two_with_doc(self, value):
+        """Larger than two with value {0}"""
+        self.assertTrue(larger_than_two(value))
+
+    @data([3, 2], [4, 3], [5, 3])
+    @unpack
+    @format_doc
+    def test_list_extrac_into_args_with_doc(self, first_value, second_value):
+        """Extract into args with first value {} and second value {}"""
+        self.assertTrue(first_value > second_value)