text: # 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 unittest
  import retworkx
  
  
  class TestMatching(unittest.TestCase):
  
      def test_valid(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 1), (2, 3)}
          self.assertTrue(retworkx.is_maximal_matching(graph, matching))
  
      def test_not_matching(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 1), (1, 2), (2, 3)}
          self.assertFalse(retworkx.is_maximal_matching(graph, matching))
  
      def test_not_maximal(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 1)}
          self.assertFalse(retworkx.is_maximal_matching(graph, matching))
  
      def test_is_matching_empty(self):
          graph = retworkx.generators.path_graph(4)
          matching = set()
          self.assertTrue(retworkx.is_matching(graph, matching))
  
      def test_is_matching_single_edge(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(1, 2)}
          self.assertTrue(retworkx.is_matching(graph, matching))
  
      def test_is_matching_valid(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 1), (2, 3)}
          self.assertTrue(retworkx.is_matching(graph, matching))
  
      def test_is_matching_invalid(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 1), (1, 2), (2, 3)}
          self.assertFalse(retworkx.is_matching(graph, matching))
  
      def test_is_matching_invalid_edge(self):
          graph = retworkx.generators.path_graph(4)
          matching = {(0, 3), (1, 2)}
          self.assertFalse(retworkx.is_matching(graph, matching))
  