[cdc_rsync] Add integration tests (#42)

[cdc_rsync] Add integration tests

This CL adds Python integration tests for cdc_rsync. To run the tests,
you need to supply a Linux host and proper configuration for cdc_rsync
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_rsync.all_tests --binary_path=C:\full\path\to\cdc_rsync.exe --user_host=user@host

Ran the tests and made sure they worked.

integration_tests/cdc_rsync/connection_test.py

@@ -0,0 +1,131 @@
+# 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_rsync connection test."""
+
+from concurrent import futures
+import socket
+import time
+
+from integration_tests.framework import utils
+from integration_tests.cdc_rsync import test_base
+
+RETURN_CODE_SUCCESS = 0
+RETURN_CODE_GENERIC_ERROR = 1
+RETURN_CODE_CONNECTION_TIMEOUT = 2
+RETURN_CODE_ADDRESS_IN_USE = 4
+
+FIRST_PORT = 44450
+LAST_PORT = 44459
+
+
+class ConnectionTest(test_base.CdcRsyncTest):
+  """cdc_rsync connection test class."""
+
+  def test_valid_instance(self):
+    """Runs rsync with --instance option for a valid id.
+
+       1) Uploads a file with --instance option instead of --ip --port.
+       2) Checks the file exists on the used instance.
+    """
+    utils.create_test_file(self.local_data_path, 1024)
+    res = utils.run_rsync(self.local_data_path, self.remote_base_dir)
+    self._assert_rsync_success(res)
+    self.assertTrue(utils.does_file_exist_remotely(self.remote_data_path))
+
+  def test_invalid_instance(self):
+    """Runs rsync with --instance option for an invalid id.
+
+       1) Uploads a file with --instance option for a non-existing id.
+       2) Checks the error message.
+    """
+    bad_host = 'bad_host'
+
+    utils.create_test_file(self.local_data_path, 1024)
+    res = utils.run_rsync(self.local_data_path,
+                          bad_host + ":" + self.remote_base_dir)
+    self.assertEqual(res.returncode, RETURN_CODE_GENERIC_ERROR)
+    self.assertIn('lost connection', str(res.stderr))
+
+  def test_contimeout(self):
+    """Runs rsync with --contimeout option for an invalid ip.
+
+       1) Uploads a file with bad IP address.
+       2) Checks the error message and that it timed out after ~5 seconds.
+       3) Uploads a file with bad IP address and --contimeout 1.
+       4) Checks the error message and that it timed out after ~1 second.
+
+    """
+    utils.create_test_file(self.local_data_path, 1024)
+    bad_host = '192.0.2.1'
+    start = time.time()
+    res = utils.run_rsync(self.local_data_path,
+                          bad_host + ":" + self.remote_base_dir)
+    elapsed_time = time.time() - start
+    self.assertGreater(elapsed_time, 4.5)
+    self.assertEqual(res.returncode, RETURN_CODE_CONNECTION_TIMEOUT)
+    self.assertIn('Error: Server connection timed out', str(res.stderr))
+
+    start = time.time()
+    res = utils.run_rsync(self.local_data_path,
+                          bad_host + ":" + self.remote_base_dir,
+                          '--contimeout=1')
+    elapsed_time = time.time() - start
+    self.assertLess(elapsed_time, 3)
+    self.assertEqual(res.returncode, RETURN_CODE_CONNECTION_TIMEOUT)
+    self.assertIn('Error: Server connection timed out', str(res.stderr))
+
+  def test_multiple_instances(self):
+    """Runs multiple instances of rsync at the same time."""
+    num_instances = LAST_PORT - FIRST_PORT + 1
+
+    local_data_paths = []
+    for n in range(num_instances):
+      path = self.local_base_dir + ('testdata_%i.dat' % n)
+      utils.create_test_file(path, 1024)
+      local_data_paths.append(path)
+
+    with futures.ThreadPoolExecutor(max_workers=num_instances) as executor:
+      res = []
+      for n in range(num_instances):
+        res.append(
+            executor.submit(utils.run_rsync, local_data_paths[n],
+                            self.remote_base_dir))
+      for r in res:
+        self._assert_rsync_success(r.result())
+
+  def test_address_in_use(self):
+    """Blocks all ports and checks that rsync fails with the expected error."""
+    sockets = []
+    try:
+      # Occupy all ports.
+      for port in range(FIRST_PORT, LAST_PORT + 1):
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sockets.append(s)
+        s.bind(('127.0.0.1', port))
+        s.listen()
+
+      # rsync shouldn't be able to find an available port now.
+      utils.create_test_file(self.local_data_path, 1024)
+      res = utils.run_rsync(self.local_data_path, self.remote_base_dir)
+      self.assertIn('All ports are already in use', str(res.stderr))
+
+    finally:
+      for s in sockets:
+        s.close()
+
+
+if __name__ == '__main__':
+  test_base.test_base.main()