FIX make backport of assert_raises_regex raise the same error as the python3 version.

Author: amueller

sklearn/utils/testing.py

@@ -88,8 +88,8 @@ def assert_raises_regex(expected_exception, expected_regexp,
                                      "%r. %r does not." %
                                      (expected_regexp, error_message))
         if not_raised:
-            raise AssertionError("Should have raised %r" %
-                                 expected_exception(expected_regexp))
+            raise AssertionError("%s not raised by %s" %
+                                 (expected_exception.__name__, callable_obj.__name__))
 
 # assert_raises_regexp is deprecated in Python 3.4 in favor of
 # assert_raises_regex but lets keep the bacward compat in scikit-learn with

sklearn/utils/tests/test_estimator_checks.py

@@ -47,9 +47,9 @@ def test_check_estimator():
     msg = "object has no attribute 'fit'"
     assert_raises_regex(AttributeError, msg, check_estimator, BaseEstimator)
     # check that fit does input validation
-    msg = "argument must be a string or a number"
+    msg = "TypeError not raised by fit"
     assert_raises_regex(AssertionError, msg, check_estimator, BaseBadClassifier)
-    # check that predict does input validation
+    # check that predict does input validation (doesn't accept dicts in input)
     msg = "Estimator doesn't check for NaN and inf in predict"
     assert_raises_regex(AssertionError, msg, check_estimator, NoCheckinPredict)
     # check for sparse matrix input handling