2 files changed, 66 insertions, 0 deletions
diff --git a/ipalib/errors.py b/ipalib/errors.py
index a25df091..70128f7c 100644
--- a/ipalib/errors.py
+++ b/ipalib/errors.py
@@ -21,6 +21,26 @@
 All custom errors raised by `ipalib` package.
 """
 
+
+class IPATypeError(TypeError):
+    """
+    TypeError subclass with standard message for easier debugging.
+
+    Also has two custom attributes:
+
+        ``type`` - The type being tested against.
+        ``value`` - The offending value that caused the exception.
+    """
+
+    format = 'need a %r; got %r'
+
+    def __init__(self, type_, value):
+        assert type(value) is not type, 'no error: %r, %r' % (type_, value)
+        self.type = type_
+        self.value = value
+        TypeError.__init__(self, self.format % (self.type, self.value))
+
+
 class IPAError(Exception):
     """
     Use this base class for your custom IPA errors unless there is a
diff --git a/ipalib/tests/test_errors.py b/ipalib/tests/test_errors.py
new file mode 100644
index 00000000..bca8d3a8
--- /dev/null
+++ b/ipalib/tests/test_errors.py
@@ -0,0 +1,46 @@
+# Authors:
+#   Jason Gerard DeRose <jderose@redhat.com>
+#
+# Copyright (C) 2008  Red Hat
+# see file 'COPYING' for use and warranty information
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; version 2 only
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+"""
+Unit tests for `ipalib.errors` module.
+"""
+
+from tstutil import raises, getitem, no_set, no_del, read_only, ClassChecker
+from ipalib import errors
+
+
+class test_IPATypeError(ClassChecker):
+    """
+    Tests the `errors.IPATypeError` exception.
+    """
+    _cls = errors.IPATypeError
+
+    def test_class(self):
+        assert self.cls.__bases__ == (TypeError,)
+
+    def test_init(self):
+        """
+        Tests the `errors.IPATypeError.__init__` method.
+        """
+        t = unicode
+        v = 'hello'
+        e = self.cls(t, v)
+        assert e.type is t
+        assert e.value is v
+        assert str(e) == 'need a %r; got %r' % (t, v)