Add utility program to print test fixture configuration

In-repo configuration means that test configs are more complex,
requiring directory hierarchies representing multiple git repos.
To aid a developer wanting to see a test configuration at a glance,
add a script to print out the relevant files.

Change-Id: I5599c72be343c0e391d8789434e7793cac83ec41

tests/print_layout.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+
+# 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 argparse
+import os
+import sys
+
+import tests.base
+
+CONFIG_DIR = os.path.join(tests.base.FIXTURE_DIR, 'config')
+
+
+def print_file(title, path):
+    print('')
+    print(title)
+    print('-' * 78)
+    with open(path) as f:
+        print(f.read())
+    print('-' * 78)
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Print test layout.')
+    parser.add_argument(dest='config', nargs='?',
+                        help='the test configuration name')
+    args = parser.parse_args()
+    if not args.config:
+        print('Available test configurations:')
+        for d in os.listdir(CONFIG_DIR):
+            print('  ' + d)
+        sys.exit(1)
+    configdir = os.path.join(CONFIG_DIR, args.config)
+
+    title = '   Configuration: %s   ' % args.config
+    print('=' * len(title))
+    print(title)
+    print('=' * len(title))
+    print_file('Main Configuration',
+               os.path.join(configdir, 'main.yaml'))
+
+    gitroot = os.path.join(configdir, 'git')
+    for gitrepo in os.listdir(gitroot):
+        reporoot = os.path.join(gitroot, gitrepo)
+        print('')
+        print('=== Git repo: %s ===' % gitrepo)
+        filenames = os.listdir(reporoot)
+        for fn in filenames:
+            if fn in ['zuul.yaml', '.zuul.yaml']:
+                print_file('File: ' + os.path.join(gitrepo, fn),
+                           os.path.join(reporoot, fn))
+
+
+if __name__ == '__main__':
+    main()