diff --git a/tests/test_hooks.py b/tests/test_hooks.py
new file mode 100644
index 0000000..ed8268d
--- /dev/null
+++ b/tests/test_hooks.py
@@ -0,0 +1,60 @@
+# -*- coding:utf-8 -*-
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# 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.
+
+"""Unittests for the hooks.py module."""
+
+from __future__ import print_function
+
+import hooks
+import unittest
+
+class RepoHookShebang(unittest.TestCase):
+  """Check shebang parsing in RepoHook."""
+
+  def test_no_shebang(self):
+    """Lines w/out shebangs should be rejected."""
+    DATA = (
+        '',
+        '# -*- coding:utf-8 -*-\n',
+        '#\n# foo\n',
+        '# Bad shebang in script\n#!/foo\n'
+    )
+    for data in DATA:
+      self.assertIsNone(hooks.RepoHook._ExtractInterpFromShebang(data))
+
+  def test_direct_interp(self):
+    """Lines whose shebang points directly to the interpreter."""
+    DATA = (
+        ('#!/foo', '/foo'),
+        ('#! /foo', '/foo'),
+        ('#!/bin/foo ', '/bin/foo'),
+        ('#! /usr/foo ', '/usr/foo'),
+        ('#! /usr/foo -args', '/usr/foo'),
+    )
+    for shebang, interp in DATA:
+      self.assertEqual(hooks.RepoHook._ExtractInterpFromShebang(shebang),
+                       interp)
+
+  def test_env_interp(self):
+    """Lines whose shebang launches through `env`."""
+    DATA = (
+        ('#!/usr/bin/env foo', 'foo'),
+        ('#!/bin/env foo', 'foo'),
+        ('#! /bin/env /bin/foo ', '/bin/foo'),
+    )
+    for shebang, interp in DATA:
+      self.assertEqual(hooks.RepoHook._ExtractInterpFromShebang(shebang),
+                       interp)