# 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 TestNeighbors(unittest.TestCase):
    def test_single_neighbor(self):
        graph = retworkx.PyGraph()
        node_a = graph.add_node("a")
        node_b = graph.add_node("b")
        graph.add_edge(node_a, node_b, {"a": 1})
        node_c = graph.add_node("c")
        graph.add_edge(node_a, node_c, {"a": 2})
        res = graph.neighbors(node_a)
        self.assertCountEqual([node_c, node_b], res)

    def test_unique_neighbors_on_graphs(self):
        dag = retworkx.PyGraph()
        node_a = dag.add_node("a")
        node_b = dag.add_node("b")
        node_c = dag.add_node("c")
        dag.add_edge(node_a, node_b, ["edge a->b"])
        dag.add_edge(node_a, node_b, ["edge a->b bis"])
        dag.add_edge(node_a, node_c, ["edge a->c"])
        res = dag.neighbors(node_a)
        self.assertCountEqual([node_c, node_b], res)

    def test_no_neighbor(self):
        graph = retworkx.PyGraph()
        node_a = graph.add_node("a")
        self.assertEqual([], graph.neighbors(node_a))
