Don't remove, just deprecate assert_raises_regex

Author: gfyoung

pandas/tests/util/test_testing.py

@@ -884,3 +884,13 @@ def test_create_temp_directory():
         assert os.path.exists(path)
         assert os.path.isdir(path)
     assert not os.path.exists(path)
+
+
+def test_assert_raises_regex_deprecated():
+    # see gh-23592
+
+    with tm.assert_produces_warning(FutureWarning):
+        msg = "Not equal!"
+
+        with tm.assert_raises_regex(AssertionError, msg):
+            assert 1 == 2, msg

pandas/util/testing.py

@@ -21,7 +21,7 @@
 import pandas.compat as compat
 from pandas.compat import (
     PY2, PY3, Counter, StringIO, callable, filter, httplib, lmap, lrange, lzip,
-    map, range, string_types, u, unichr, zip)
+    map, raise_with_traceback, range, string_types, u, unichr, zip)
 
 from pandas.core.dtypes.common import (
     is_bool, is_categorical_dtype, is_datetimelike_v_numeric,
@@ -2532,6 +2532,137 @@ def wrapper(*args, **kwargs):
 with_connectivity_check = network
 
 
+def assert_raises_regex(_exception, _regexp, _callable=None,
+                        *args, **kwargs):
+    r"""
+    Check that the specified Exception is raised and that the error message
+    matches a given regular expression pattern. This may be a regular
+    expression object or a string containing a regular expression suitable
+    for use by `re.search()`. This is a port of the `assertRaisesRegexp`
+    function from unittest in Python 2.7.
+
+    .. deprecated:: 0.24.0
+        Use `pytest.raises` instead.
+
+    Examples
+    --------
+    >>> assert_raises_regex(ValueError, 'invalid literal for.*XYZ', int, 'XYZ')
+    >>> import re
+    >>> assert_raises_regex(ValueError, re.compile('literal'), int, 'XYZ')
+
+    If an exception of a different type is raised, it bubbles up.
+
+    >>> assert_raises_regex(TypeError, 'literal', int, 'XYZ')
+    Traceback (most recent call last):
+        ...
+    ValueError: invalid literal for int() with base 10: 'XYZ'
+    >>> dct = dict()
+    >>> assert_raises_regex(KeyError, 'pear', dct.__getitem__, 'apple')
+    Traceback (most recent call last):
+        ...
+    AssertionError: "pear" does not match "'apple'"
+
+    You can also use this in a with statement.
+
+    >>> with assert_raises_regex(TypeError, r'unsupported operand type\(s\)'):
+    ...     1 + {}
+    >>> with assert_raises_regex(TypeError, 'banana'):
+    ...     'apple'[0] = 'b'
+    Traceback (most recent call last):
+        ...
+    AssertionError: "banana" does not match "'str' object does not support \
+item assignment"
+    """
+    warnings.warn(("assert_raises_regex has been deprecated and will "
+                   "be removed in the next release. Please use "
+                   "`pytest.raises` instead."), FutureWarning, stacklevel=2)
+
+    manager = _AssertRaisesContextmanager(exception=_exception, regexp=_regexp)
+    if _callable is not None:
+        with manager:
+            _callable(*args, **kwargs)
+    else:
+        return manager
+
+
+class _AssertRaisesContextmanager(object):
+    """
+    Context manager behind `assert_raises_regex`.
+    """
+
+    def __init__(self, exception, regexp=None):
+        """
+        Initialize an _AssertRaisesContextManager instance.
+
+        Parameters
+        ----------
+        exception : class
+            The expected Exception class.
+        regexp : str, default None
+            The regex to compare against the Exception message.
+        """
+
+        self.exception = exception
+
+        if regexp is not None and not hasattr(regexp, "search"):
+            regexp = re.compile(regexp, re.DOTALL)
+
+        self.regexp = regexp
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, trace_back):
+        expected = self.exception
+
+        if not exc_type:
+            exp_name = getattr(expected, "__name__", str(expected))
+            raise AssertionError("{name} not raised.".format(name=exp_name))
+
+        return self.exception_matches(exc_type, exc_value, trace_back)
+
+    def exception_matches(self, exc_type, exc_value, trace_back):
+        """
+        Check that the Exception raised matches the expected Exception
+        and expected error message regular expression.
+
+        Parameters
+        ----------
+        exc_type : class
+            The type of Exception raised.
+        exc_value : Exception
+            The instance of `exc_type` raised.
+        trace_back : stack trace object
+            The traceback object associated with `exc_value`.
+
+        Returns
+        -------
+        is_matched : bool
+            Whether or not the Exception raised matches the expected
+            Exception class and expected error message regular expression.
+
+        Raises
+        ------
+        AssertionError : The error message provided does not match
+                         the expected error message regular expression.
+        """
+
+        if issubclass(exc_type, self.exception):
+            if self.regexp is not None:
+                val = str(exc_value)
+
+                if not self.regexp.search(val):
+                    msg = '"{pat}" does not match "{val}"'.format(
+                        pat=self.regexp.pattern, val=val)
+                    e = AssertionError(msg)
+                    raise_with_traceback(e, trace_back)
+
+            return True
+        else:
+            # Failed, so allow Exception to bubble up.
+            return False
+
+
 @contextmanager
 def assert_produces_warning(expected_warning=Warning, filter_level="always",
                             clear=None, check_stacklevel=True):