Add par_test

This test adds a number of checks for the visible python state inside a
hermetic par file.

Test: build/soong/python/tests/runtests.sh
Change-Id: I7188d862a309a09623169e1f967bde86707d41af

python/tests/testpkg/par_test.py

@@ -0,0 +1,37 @@
+# Copyright 2018 Google Inc. All rights reserved.
+#
+# 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 os
+import sys
+
+# This file checks the visible python state against expected values when run
+# inside a hermetic par file.
+
+failed = False
+def assert_equal(what, a, b):
+    global failed
+    if a != b:
+        print("Expected %s('%s') == '%s'" % (what, a, b))
+        failed = True
+
+archive = sys.modules["__main__"].__loader__.archive
+
+assert_equal("__name__", __name__, "testpkg.par_test")
+assert_equal("__file__", __file__, os.path.join(archive, "testpkg/par_test.py"))
+assert_equal("__package__", __package__, "testpkg")
+assert_equal("__loader__.archive", __loader__.archive, archive)
+assert_equal("__loader__.prefix", __loader__.prefix, "testpkg/")
+
+if failed:
+    sys.exit(1)