# test_structuralholes.py - unit tests for the structuralholes module
#
# Copyright 2017 NetworkX developers.
#
# This file is part of NetworkX.
#
# NetworkX is distributed under a BSD license; see LICENSE.txt for more
# information.
"""Unit tests for the :mod:`networkx.algorithms.structuralholes` module."""
from nose.tools import assert_almost_equal, assert_true

import math
import networkx as nx


class TestStructuralHoles(object):
    """Unit tests for computing measures of structural holes.

    The expected values for these functions were originally computed using the
    proprietary software `UCINET`_ and the free software `IGraph`_ , and then
    computed by hand to make sure that the results are correct.

    .. _UCINET: https://sites.google.com/site/ucinetsoftware/home
    .. _IGraph: http://igraph.org/

    """

    def setup(self):
        self.D = nx.DiGraph()
        self.D.add_edges_from([(0, 1), (0, 2), (1, 0), (2, 1)])
        self.D_weights = {(0, 1): 2, (0, 2): 2, (1, 0): 1, (2, 1): 1}
        # Example from http://www.analytictech.com/connections/v20(1)/holes.htm
        self.G = nx.Graph()
        self.G.add_edges_from([
            ('A', 'B'), ('A', 'F'), ('A', 'G'), ('A', 'E'), ('E', 'G'),
            ('F', 'G'), ('B', 'G'), ('B', 'D'), ('D', 'G'), ('G', 'C'),
        ])
        self.G_weights = {
            ('A', 'B'): 2, ('A', 'F'): 3, ('A', 'G'): 5, ('A', 'E'): 2,
            ('E', 'G'): 8, ('F', 'G'): 3, ('B', 'G'): 4, ('B', 'D'): 1,
            ('D', 'G'): 3, ('G', 'C'): 10,
        }

    def test_constraint_directed(self):
        constraint = nx.constraint(self.D)
        assert_almost_equal(round(constraint[0], 3), 1.003)
        assert_almost_equal(round(constraint[1], 3), 1.003)
        assert_almost_equal(round(constraint[2], 3), 1.389)

    def test_effective_size_directed(self):
        effective_size = nx.effective_size(self.D)
        assert_almost_equal(round(effective_size[0], 3), 1.167)
        assert_almost_equal(round(effective_size[1], 3), 1.167)
        assert_almost_equal(round(effective_size[2], 3), 1)

    def test_constraint_weighted_directed(self):
        D = self.D.copy()
        nx.set_edge_attributes(D, self.D_weights, 'weight')
        constraint = nx.constraint(D, weight='weight')
        assert_almost_equal(round(constraint[0], 3), 0.840)
        assert_almost_equal(round(constraint[1], 3), 1.143)
        assert_almost_equal(round(constraint[2], 3), 1.378)

    def test_effective_size_weighted_directed(self):
        D = self.D.copy()
        nx.set_edge_attributes(D, self.D_weights, 'weight')
        effective_size = nx.effective_size(D, weight='weight')
        assert_almost_equal(round(effective_size[0], 3), 1.567)
        assert_almost_equal(round(effective_size[1], 3), 1.083)
        assert_almost_equal(round(effective_size[2], 3), 1)

    def test_constraint_undirected(self):
        constraint = nx.constraint(self.G)
        assert_almost_equal(round(constraint['G'], 3), 0.400)
        assert_almost_equal(round(constraint['A'], 3), 0.595)
        assert_almost_equal(round(constraint['C'], 3), 1)

    def test_effective_size_undirected_borgatti(self):
        effective_size = nx.effective_size(self.G)
        assert_almost_equal(round(effective_size['G'], 2), 4.67)
        assert_almost_equal(round(effective_size['A'], 2), 2.50)
        assert_almost_equal(round(effective_size['C'], 2), 1)

    def test_effective_size_undirected(self):
        G = self.G.copy()
        nx.set_edge_attributes(G, 1, 'weight')
        effective_size = nx.effective_size(G, weight='weight')
        assert_almost_equal(round(effective_size['G'], 2), 4.67)
        assert_almost_equal(round(effective_size['A'], 2), 2.50)
        assert_almost_equal(round(effective_size['C'], 2), 1)

    def test_constraint_weighted_undirected(self):
        G = self.G.copy()
        nx.set_edge_attributes(G, self.G_weights, 'weight')
        constraint = nx.constraint(G, weight='weight')
        assert_almost_equal(round(constraint['G'], 3), 0.299)
        assert_almost_equal(round(constraint['A'], 3), 0.795)
        assert_almost_equal(round(constraint['C'], 3), 1)

    def test_effective_size_weighted_undirected(self):
        G = self.G.copy()
        nx.set_edge_attributes(G, self.G_weights, 'weight')
        effective_size = nx.effective_size(G, weight='weight')
        assert_almost_equal(round(effective_size['G'], 2), 5.47)
        assert_almost_equal(round(effective_size['A'], 2), 2.47)
        assert_almost_equal(round(effective_size['C'], 2), 1)

    def test_constraint_isolated(self):
        G = self.G.copy()
        G.add_node(1)
        constraint = nx.constraint(G)
        assert_true(math.isnan(constraint[1]))

    def test_effective_size_isolated(self):
        G = self.G.copy()
        G.add_node(1)
        nx.set_edge_attributes(G, self.G_weights, 'weight')
        effective_size = nx.effective_size(G, weight='weight')
        assert_true(math.isnan(effective_size[1]))

    def test_effective_size_borgatti_isolated(self):
        G = self.G.copy()
        G.add_node(1)
        effective_size = nx.effective_size(G)
        assert_true(math.isnan(effective_size[1]))