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 TestStarGraph(unittest.TestCase):
      def test_directed_star_graph(self):
          graph = retworkx.generators.directed_star_graph(20)
          self.assertEqual(len(graph), 20)
          self.assertEqual(len(graph.edges()), 19)
          expected_edges = [(0, i, None) for i in range(1, 20)]
          self.assertEqual(sorted(graph.out_edges(0)), sorted(expected_edges))
  
      def test_star_directed_graph_inward(self):
          graph = retworkx.generators.directed_star_graph(20, inward=True)
          self.assertEqual(len(graph), 20)
          self.assertEqual(len(graph.edges()), 19)
          expected_edges = [(i, 0, None) for i in range(1, 20)]
          self.assertEqual(sorted(graph.in_edges(0)), sorted(expected_edges))
  
      def test_directed_star_graph_weights(self):
          graph = retworkx.generators.directed_star_graph(weights=list(range(20)))
          self.assertEqual(len(graph), 20)
          self.assertEqual([x for x in range(20)], graph.nodes())
          self.assertEqual(len(graph.edges()), 19)
          expected_edges = sorted([(0, i, None) for i in range(1, 20)])
          self.assertEqual(sorted(graph.out_edges(0)), expected_edges)
  
      def test_directed_star_graph_bidirectional(self):
          graph = retworkx.generators.directed_star_graph(20, bidirectional=True)
          outw = []
          inw = []
          for i in range(1, 20):
              outw.append((0, i, None))
              inw.append((i, 0, None))
              self.assertEqual(graph.out_edges(i), [(i, 0, None)])
              self.assertEqual(graph.in_edges(i), [(0, i, None)])
          self.assertEqual(graph.out_edges(0), outw[::-1])
          self.assertEqual(graph.in_edges(0), inw[::-1])
  
      def test_directed_star_graph_bidirectional_inward(self):
          graph = retworkx.generators.directed_star_graph(
              20, bidirectional=True, inward=True
          )
          outw = []
          inw = []
          for i in range(1, 20):
              outw.append((0, i, None))
              inw.append((i, 0, None))
              self.assertEqual(graph.out_edges(i), [(i, 0, None)])
              self.assertEqual(graph.in_edges(i), [(0, i, None)])
          self.assertEqual(graph.out_edges(0), outw[::-1])
          self.assertEqual(graph.in_edges(0), inw[::-1])
          graph = retworkx.generators.directed_star_graph(
              20, bidirectional=True, inward=False
          )
          outw = []
          inw = []
          for i in range(1, 20):
              outw.append((0, i, None))
              inw.append((i, 0, None))
              self.assertEqual(graph.out_edges(i), [(i, 0, None)])
              self.assertEqual(graph.in_edges(i), [(0, i, None)])
          self.assertEqual(graph.out_edges(0), outw[::-1])
          self.assertEqual(graph.in_edges(0), inw[::-1])
  
      def test_star_directed_graph_weights_inward(self):
          graph = retworkx.generators.directed_star_graph(
              weights=list(range(20)), inward=True
          )
          self.assertEqual(len(graph), 20)
          self.assertEqual([x for x in range(20)], graph.nodes())
          self.assertEqual(len(graph.edges()), 19)
          expected_edges = [(i, 0, None) for i in range(1, 20)]
          self.assertEqual(sorted(graph.in_edges(0)), sorted(expected_edges))
  
      def test_star_directed_no_weights_or_num(self):
          with self.assertRaises(IndexError):
              retworkx.generators.directed_star_graph()
  
      def test_star_graph(self):
          graph = retworkx.generators.star_graph(20)
          self.assertEqual(len(graph), 20)
          self.assertEqual(len(graph.edges()), 19)
  
      def test_star_graph_weights(self):
          graph = retworkx.generators.star_graph(weights=list(range(20)))
          self.assertEqual(len(graph), 20)
          self.assertEqual([x for x in range(20)], graph.nodes())
          self.assertEqual(len(graph.edges()), 19)
  
      def test_star_no_weights_or_num(self):
          with self.assertRaises(IndexError):
              retworkx.generators.star_graph()
  