1 files changed, 29 insertions, 32 deletions
diff --git a/coverage/misc.py b/coverage/misc.py
index d5197ea3..d11ebccb 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -1,4 +1,7 @@
-"""Miscellaneous stuff for Coverage."""
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
+
+"""Miscellaneous stuff for coverage.py."""
 
 import errno
 import hashlib
@@ -6,7 +9,30 @@ import inspect
 import os
 
 from coverage import env
-from coverage.backward import string_class, to_bytes
+from coverage.backward import string_class, to_bytes, unicode_class
+
+
+# Use PyContracts for assertion testing on parameters and returns, but only if
+# we are running our own test suite.
+if env.TESTING:
+    from contracts import contract              # pylint: disable=unused-import
+    from contracts import new_contract
+
+    try:
+        # Define contract words that PyContract doesn't have.
+        new_contract('bytes', lambda v: isinstance(v, bytes))
+        if env.PY3:
+            new_contract('unicode', lambda v: isinstance(v, unicode_class))
+    except ValueError:
+        # During meta-coverage, this module is imported twice, and PyContracts
+        # doesn't like redefining contracts. It's OK.
+        pass
+else:                                           # pragma: not covered
+    # We aren't using real PyContracts, so just define a no-op decorator as a
+    # stunt double.
+    def contract(**unused):
+        """Dummy no-op implementation of `contract`."""
+        return lambda func: func
 
 
 def nice_pair(pair):
@@ -56,12 +82,6 @@ def format_lines(statements, lines):
     return ret
 
 
-def short_stack():                                          # pragma: debugging
-    """Return a string summarizing the call stack."""
-    stack = inspect.stack()[:0:-1]
-    return "\n".join("%30s : %s @%d" % (t[3], t[1], t[2]) for t in stack)
-
-
 def expensive(fn):
     """A decorator to cache the result of an expensive operation.
 
@@ -139,29 +159,6 @@ class Hasher(object):
         return self.md5.hexdigest()
 
 
-def overrides(obj, method_name, base_class):
-    """Does `obj` override the `method_name` it got from `base_class`?
-
-    Determine if `obj` implements the method called `method_name`, which it
-    inherited from `base_class`.
-
-    Returns a boolean.
-
-    """
-    klass = obj.__class__
-    klass_func = getattr(klass, method_name)
-    base_func = getattr(base_class, method_name)
-
-    # Python 2/3 compatibility: Python 2 returns an instancemethod object, the
-    # function is the .im_func attribute.  Python 3 returns a plain function
-    # object already.
-    if env.PY2:
-        klass_func = klass_func.im_func
-        base_func = base_func.im_func
-
-    return klass_func is not base_func
-
-
 # TODO: abc?
 def _needs_to_implement(that, func_name):
     """Helper to raise NotImplementedError in interface stubs."""
@@ -181,7 +178,7 @@ def _needs_to_implement(that, func_name):
 
 
 class CoverageException(Exception):
-    """An exception specific to Coverage."""
+    """An exception specific to coverage.py."""
     pass