222: Fixed broken assertion in IPATypeError; did more work on docstrings in same

ipalib/errors.py

@@ -24,18 +24,22 @@ All custom errors raised by `ipalib` package.
 
 class IPATypeError(TypeError):
     """
-    TypeError subclass with standard message for easier debugging.
+    A TypeError subclass with with a standard message.
 
     Also has two custom attributes:
 
         ``type`` - The type being tested against.
         ``value`` - The offending value that caused the exception.
+
+    There is no edict that all TypeError should be raised with IPATypeError,
+    but when it fits, use it... it makes the unit tests faster to write and
+    the debugging easier to read.
     """
 
     format = 'need a %r; got %r'
 
     def __init__(self, type_, value):
-        assert type(value) is not type, 'no error: %r, %r' % (type_, value)
+        assert type(value) is not type_, '%r is a %r' % (value, type_)
         self.type = type_
         self.value = value
         TypeError.__init__(self, self.format % (self.type, self.value))

ipalib/tests/test_errors.py

@@ -21,7 +21,7 @@
 Unit tests for `ipalib.errors` module.
 """
 
-from tstutil import raises, getitem, no_set, no_del, read_only, ClassChecker
+from tstutil import raises, ClassChecker
 from ipalib import errors
 
 
@@ -38,9 +38,14 @@ class test_IPATypeError(ClassChecker):
         """
         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)
+        type_ = unicode
+        okay = 'hello'
+        e = self.cls(type_, okay)
+        assert e.type is type_
+        assert e.value is okay
+        assert str(e) == 'need a %r; got %r' % (type_, okay)
+
+        # Check that AssertionError is raised when type(value) is type_:
+        fail = u'hello'
+        e = raises(AssertionError, self.cls, type_, fail)
+        assert str(e) == '%r is a %r' % (fail, type_)