Add test to ensure we don't duplicate filenames

Add a new test_no_dup_filenames module to help ensure we don't have
duplicate names across elements.

Change-Id: I2af4a614f71fe58eba04e3fc50d3c0a70dd91f71

diskimage_builder/tests/test_no_dup_filenames.py

@@ -0,0 +1,41 @@
+# Copyright 2014 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import glob
+import os
+
+
+import testtools
+
+
+class TestNoDupFilenames(testtools.TestCase):
+
+    def test_no_dup_filenames(self):
+        topdir = os.path.normpath(os.path.dirname(__file__) + '/../../')
+        elements_glob = os.path.join(topdir, "elements", "*")
+
+        filenames = []
+        dirs_to_check = ['block-device.d', 'cleanup.d', 'extra-data.d',
+                         'finalise.d', 'install.d', 'post-install.d',
+                         'pre-install.d', 'root.d']
+
+        for element_dir in glob.iglob(elements_glob):
+            for dir_to_check in dirs_to_check:
+                target_dir = os.path.join(element_dir, dir_to_check, "*")
+                for target in glob.iglob(target_dir):
+                    short_path = target[len(element_dir) + 1:]
+                    if not os.path.isdir(target):
+                        err_msg = 'Duplicate file name found %s' % short_path
+                        self.assertFalse(short_path in filenames, err_msg)
+                        filenames.append(short_path)