public void AddVertex_WhenNewVertexId_ThenCreatedVertex()
{
// given
int newVertexId = 13;
string property = "qwerty";
// when
Vertex <int> result = testObject.AddVertex(newVertexId, property);
// then
result.Id.Should().Be(newVertexId);
testObject.VerticesCount.Should().Be(11);
testObject.GetNeighbours(result).Should().BeEmpty();
testObject.Properties[result].Should().Be(property);
}
public IEnumerable <Vertex <TVertexId> > GetNeighbours(Vertex <TVertexId> vertex) => graph.GetNeighbours(vertex);