diff --git a/python/tests/par_test.py b/python/tests/par_test.py
new file mode 100644
index 0000000..1fafe0f
--- /dev/null
+++ b/python/tests/par_test.py
@@ -0,0 +1,50 @@
+# Copyright 2019 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 site
+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
+
+assert_equal("__name__", __name__, "__main__")
+assert_equal("os.path.basename(__file__)", os.path.basename(__file__), "par_test.py")
+
+archive = os.path.dirname(__file__)
+
+assert_equal("__package__", __package__, "")
+assert_equal("sys.argv[0]", sys.argv[0], archive)
+assert_equal("sys.executable", sys.executable, None)
+assert_equal("sys.exec_prefix", sys.exec_prefix, archive)
+assert_equal("sys.prefix", sys.prefix, archive)
+assert_equal("__loader__.archive", __loader__.archive, archive)
+assert_equal("site.ENABLE_USER_SITE", site.ENABLE_USER_SITE, None)
+
+assert_equal("len(sys.path)", len(sys.path), 3)
+assert_equal("sys.path[0]", sys.path[0], archive)
+assert_equal("sys.path[1]", sys.path[1], os.path.join(archive, "internal"))
+assert_equal("sys.path[2]", sys.path[2], os.path.join(archive, "internal", "stdlib"))
+
+if failed:
+    sys.exit(1)
+
+import testpkg.par_test