Index: Lib/unittest/loader.py
===================================================================
--- Lib/unittest/loader.py	(revision 79608)
+++ Lib/unittest/loader.py	(working copy)
@@ -84,6 +84,31 @@
                                                self.suiteClass)
         return tests
 
+    # The stack-walking code of this method was taken from--
+    #
+    # http://twistedmatrix.com/trac/browser/trunk/twisted/python/reflect.py#L382
+    def _importWithExceptionCheck(self, module_name, module_not_found):
+        """Import the given module while checking for a module not found.
+
+        The module_not_found parameter should be an empty list.  If this
+        method raises an exception due to a module not found, then the
+        method adds an element to module_not_found so it evaluates True.
+        This allows the original exception to bubble up untouched.
+
+        """
+        try:
+            return __import__(module_name)
+        except ImportError, err:
+            excType, excValue, excTraceback = sys.exc_info()
+            while excTraceback:
+                execName = excTraceback.tb_frame.f_globals["__name__"]
+                if (execName is None or # python 2.4+, post-cleanup
+                    execName == module_name): # python 2.3, no cleanup
+                    raise excType, excValue, excTraceback
+                excTraceback = excTraceback.tb_next
+            module_not_found.append(1)
+            raise excType, excValue, excTraceback
+
     def loadTestsFromName(self, name, module=None):
         """Return a suite of all tests cases given a string specifier.
 
@@ -98,11 +123,14 @@
             parts_copy = parts[:]
             while parts_copy:
                 try:
-                    module = __import__('.'.join(parts_copy))
+                    import_name = '.'.join(parts_copy)
+                    module_not_found = []
+                    module = self._importWithExceptionCheck(import_name,
+                                                            module_not_found)
                     break
                 except ImportError:
                     del parts_copy[-1]
-                    if not parts_copy:
+                    if not parts_copy or not module_not_found:
                         raise
             parts = parts[1:]
         obj = module