[cdc_stream] Add integration tests (#44)

This CL adds Python integration tests for cdc_stream. To run the
tests, you need to supply a Linux host and proper configuration for
cdc_stream to work:

set CDC_SSH_COMMAND=C:\path\to\ssh.exe <args>
set CDC_SCP_COMMAND=C:\path\to\scp.exe <args>
C:\python38\python.exe -m integration_tests.cdc_stream.all_tests --binary_path=C:\full\path\to\cdc_stream.exe --user_host=user@host

Ran the tests and made sure they worked.

integration_tests/cdc_stream/directory_test.py

@@ -0,0 +1,124 @@
+# Copyright 2022 Google LLC
+#
+# 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.
+
+# Lint as: python3
+"""cdc_stream directory Test."""
+
+import os
+
+from integration_tests.framework import utils
+from integration_tests.cdc_stream import test_base
+
+
+class DirectoryTest(test_base.CdcStreamTest):
+  """cdc_stream test class for modifications of streamed directory."""
+
+  def _assert_mount_fails(self, directory):
+    """Check that mounting a directory fails.
+
+    Args:
+        directory (string): name of a file/directory to be streamed.
+    """
+    with self.assertRaises(Exception):
+      self._start(directory)
+
+  def test_recreate_streamed_dir(self):
+    """Survive recreation of a streamed directory.
+
+    Streamed directory layout:
+       |-- rootdir
+       |   |-- dir1
+       |      |-- emptydir2
+       |      |-- file1_1.txt
+       |      |-- file1_2.txt
+       |   |-- dir2
+       |      |-- file2_1.txt
+       |   |-- emptydir1
+       |   |-- file0.txt
+    """
+    files = [
+        'dir1\\file1_1.txt', 'dir1\\file1_2.txt', 'dir2\\file2_1.txt',
+        'file0.txt'
+    ]
+    dirs = ['dir1\\emptydir2\\', 'emptydir1\\', 'dir1\\', 'dir2\\']
+    self._create_test_data(files, dirs)
+    self._start()
+    self._test_dir_content(files=files, dirs=dirs)
+    self._assert_cache()
+    self._assert_cdc_fuse_mounted()
+    original = utils.get_ssh_command_output(self.ls_cmd)
+
+    # Remove directory on workstation => empty directory on gamelet.
+    utils.remove_test_directory(self.local_base_dir)
+    self.assertTrue(self._wait_until_remote_dir_changed(original))
+    self._test_dir_content(files=[], dirs=[])
+    self._assert_cdc_fuse_mounted()
+
+    original = utils.get_ssh_command_output(self.ls_cmd)
+    # Recreate directory, add files => the content becomes visible again.
+    self._create_test_data(files, dirs)
+    self.assertTrue(self._wait_until_remote_dir_changed(original))
+    self._test_dir_content(files=files, dirs=dirs)
+    self._assert_cdc_fuse_mounted()
+
+  def test_non_existing_streamed_dir_fail(self):
+    """Fail if the streamed directory does not exist."""
+    streamed_dir = os.path.join(self.local_base_dir, 'non_existing')
+    self._assert_mount_fails(streamed_dir)
+    self._test_dir_content(files=[], dirs=[])
+    self._assert_cdc_fuse_mounted(success=False)
+
+  def test_streamed_dir_as_file_fail(self):
+    """Fail if the streamed path is a file."""
+    streamed_file = os.path.join(self.local_base_dir, 'file')
+    utils.create_test_file(streamed_file, 1024)
+    self._assert_mount_fails(streamed_file)
+    self._test_dir_content(files=[], dirs=[])
+    self._assert_cdc_fuse_mounted(success=False)
+
+  def test_remount_recreated_streamed_dir(self):
+    """Remounting a directory, which is currently removed, stops streaming session."""
+    files = [
+        'dir1\\file1_1.txt', 'dir1\\file1_2.txt', 'dir2\\file2_1.txt',
+        'file0.txt'
+    ]
+    dirs = ['dir1\\emptydir2\\', 'emptydir1\\', 'dir1\\', 'dir2\\']
+    self._create_test_data(files, dirs)
+    self._start()
+    self._test_dir_content(files=files, dirs=dirs)
+    self._assert_cache()
+    self._assert_cdc_fuse_mounted()
+    original = utils.get_ssh_command_output(self.ls_cmd)
+
+    # Remove directory on workstation => empty directory on gamelet.
+    utils.remove_test_directory(self.local_base_dir)
+    self.assertTrue(self._wait_until_remote_dir_changed(original))
+    self._test_dir_content(files=[], dirs=[])
+    self._assert_cdc_fuse_mounted()
+
+    # Remount for the same directory fails and stops an existing session.
+    self._assert_mount_fails(self.local_base_dir)
+    self._test_dir_content(files=[], dirs=[])
+
+    # Create a new folder and mount -> should succeed.
+    test_dir = 'Temp'
+    file_name = 'test_file.txt'
+    utils.create_test_file(
+        os.path.join(self.local_base_dir, test_dir, file_name), 100)
+    self._start(os.path.join(self.local_base_dir, test_dir))
+    self._assert_remote_dir_matches([file_name])
+
+
+if __name__ == '__main__':
+  test_base.test_base.main()