[Build System: build-script] Added a new run_test.py script to utils/swift_build_support which is used to run the unit test suite.

Author: Ross Bayer

Diff for: utils/swift_build_support/README.md

@@ -6,5 +6,5 @@ structures used by the Swift build script.
 You may run unit tests for `swift_build_support` from the command line:
 
 ```sh
-apple/swift $ python -m unittest discover -s utils/swift_build_support
+$ python utils/swift_build_support/run_tests.py
 ```

Diff for: utils/swift_build_support/run_tests.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+
+"""
+Small script used to easily run the swift_build_support module unit tests.
+"""
+
+
+from __future__ import absolute_import, unicode_literals
+
+import os
+import sys
+import unittest
+
+
+MODULE_DIR = os.path.abspath(os.path.dirname(__file__))
+UTILS_DIR = os.path.abspath(os.path.join(MODULE_DIR, os.pardir))
+
+
+if __name__ == '__main__':
+    # Add the swift/utils directory to the Python path.
+    sys.path.append(UTILS_DIR)
+
+    # Discover all tests for the module.
+    module_tests = unittest.defaultTestLoader.discover(MODULE_DIR)
+
+    # Create and run test suite.
+    suite = unittest.TestSuite()
+    suite.addTests(module_tests)
+
+    runner = unittest.TextTestRunner()
+    result = runner.run(suite)
+
+    sys.exit(not result.wasSuccessful())

Diff for: utils/swift_build_support/test_swift_build_support.sh

@@ -7,4 +7,4 @@
 // UNSUPPORTED: OS=tvos
 // UNSUPPORTED: OS=watchos
 
-// RUN: env PYTHONPATH=%utils:$PYTHONPATH %{python} -m unittest discover -s %utils/swift_build_support
+// RUN: %{python} %utils/swift_build_support/run_tests.py