Restore checking PyPy3 (#3514)

* Resotre checking PyPy3.

I don't know why it was removed but PyPy3 now supports Python 3.5 and hopefully the next major PyPy version will support PyPy 3.6.

* Fix pypy name.

* Reduce test dependency on items order.

* Change planar_drawing test and allow edge order flips in tests

10 files changed, 36 insertions, 26 deletions

diff --git a/.travis.yml b/.travis.yml
index 1c64ae40..805f6294 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -67,6 +67,9 @@ matrix:
     - python: 3.7
       dist: xenial
       sudo: true
+    - python: pypy3.5-7.0
+      dist: xenial
+      sudo: true
 
 before_install:
   # prepare the system to install prerequisites or dependencies
diff --git a/networkx/algorithms/bipartite/projection.py b/networkx/algorithms/bipartite/projection.py
index f0b8580e..69c5f6bd 100644
--- a/networkx/algorithms/bipartite/projection.py
+++ b/networkx/algorithms/bipartite/projection.py
@@ -144,7 +144,7 @@ def weighted_projected_graph(B, nodes, ratio=False):
 
     ratio: Bool (default=False)
         If True, edge weight is the ratio between actual shared neighbors
-        and maximum possible shared neighbors (i.e., the size of the other 
+        and maximum possible shared neighbors (i.e., the size of the other
         node set). If False, edges weight is the number of shared neighbors.
 
     Returns
@@ -255,7 +255,7 @@ def collaboration_weighted_projected_graph(B, nodes):
     >>> G = bipartite.collaboration_weighted_projected_graph(B, [0, 2, 4, 5])
     >>> list(G)
     [0, 2, 4, 5]
-    >>> for edge in G.edges(data=True): print(edge)
+    >>> for edge in sorted(G.edges(data=True)): print(edge)
     ...
     (0, 2, {'weight': 0.5})
     (0, 5, {'weight': 0.5})
@@ -454,7 +454,7 @@ def generic_weighted_projected_graph(B, nodes, weight_function=None):
     >>> # Add some arbitrary weight to the edges
     >>> for i,(u,v) in enumerate(B.edges()):
     ...     B.edges[u, v]['weight'] = i + 1
-    ... 
+    ...
     >>> for edge in B.edges(data=True):
     ...     print(edge)
     ...
diff --git a/networkx/algorithms/chordal.py b/networkx/algorithms/chordal.py
index c609cfde..b66f8ce6 100644
--- a/networkx/algorithms/chordal.py
+++ b/networkx/algorithms/chordal.py
@@ -117,7 +117,7 @@ def find_induced_nodes(G, s, t, treewidth_bound=sys.maxsize):
     >>> G=nx.Graph()
     >>> G = nx.generators.classic.path_graph(10)
     >>> I = nx.find_induced_nodes(G,1,9,2)
-    >>> list(I)
+    >>> sorted(list(I))
     [1, 2, 3, 4, 5, 6, 7, 8, 9]
 
     Notes
diff --git a/networkx/algorithms/community/kclique.py b/networkx/algorithms/community/kclique.py
index 34ade574..45220440 100644
--- a/networkx/algorithms/community/kclique.py
+++ b/networkx/algorithms/community/kclique.py
@@ -24,7 +24,7 @@ def k_clique_communities(G, k, cliques=None):
     k : int
        Size of smallest clique
 
-    cliques: list or generator       
+    cliques: list or generator
        Precomputed cliques (use networkx.find_cliques(G))
 
     Returns
@@ -38,7 +38,7 @@ def k_clique_communities(G, k, cliques=None):
     >>> K5 = nx.convert_node_labels_to_integers(G,first_label=2)
     >>> G.add_edges_from(K5.edges())
     >>> c = list(k_clique_communities(G, 4))
-    >>> list(c[0])
+    >>> sorted(list(c[0]))
     [0, 1, 2, 3, 4, 5, 6]
     >>> list(k_clique_communities(G, 6))
     []
@@ -46,7 +46,7 @@ def k_clique_communities(G, k, cliques=None):
     References
     ----------
     .. [1] Gergely Palla, Imre Derényi, Illés Farkas1, and Tamás Vicsek,
-       Uncovering the overlapping community structure of complex networks 
+       Uncovering the overlapping community structure of complex networks
        in nature and society Nature 435, 814-818, 2005,
        doi:10.1038/nature03607
     """
diff --git a/networkx/algorithms/cycles.py b/networkx/algorithms/cycles.py
index 7ff99fcc..bc108682 100644
--- a/networkx/algorithms/cycles.py
+++ b/networkx/algorithms/cycles.py
@@ -526,7 +526,7 @@ def minimum_cycle_basis(G, weight=None):
     >>> G=nx.Graph()
     >>> G.add_cycle([0,1,2,3])
     >>> G.add_cycle([0,3,4,5])
-    >>> print(nx.minimum_cycle_basis(G))
+    >>> print([sorted(c) for c in nx.minimum_cycle_basis(G)])
     [[0, 1, 2, 3], [0, 3, 4, 5]]
 
     References:
diff --git a/networkx/algorithms/tests/test_clique.py b/networkx/algorithms/tests/test_clique.py
index 97a0765e..1c2fecc3 100644
--- a/networkx/algorithms/tests/test_clique.py
+++ b/networkx/algorithms/tests/test_clique.py
@@ -25,10 +25,11 @@ class TestCliques:
     def test_selfloops(self):
         self.G.add_edge(1, 1)
         cl = list(nx.find_cliques(self.G))
-        rcl = nx.find_cliques_recursive(self.G)
-        assert_equal(sorted(map(sorted, cl)), sorted(map(sorted, rcl)))
-        assert_equal(cl,
-                     [[2, 6, 1, 3], [2, 6, 4], [5, 4, 7], [8, 9], [10, 11]])
+        rcl = list(nx.find_cliques_recursive(self.G))
+        assert_equal(set(map(frozenset, cl)), set(map(frozenset, rcl)))
+        answer = [{2, 6, 1, 3}, {2, 6, 4}, {5, 4, 7}, {8, 9}, {10, 11}]
+        assert_equal(len(answer), len(cl))
+        assert_true(all(set(c) in answer for c in cl))
 
     def test_find_cliques2(self):
         hcl = list(nx.find_cliques(self.H))
@@ -93,16 +94,21 @@ class TestCliques:
                      [[2, 6, 1, 3]])
         assert_equal(list(nx.cliques_containing_node(G, [1]).values()),
                      [[[2, 6, 1, 3]]])
-        assert_equal(list(nx.cliques_containing_node(G, [1, 2]).values()),
+        assert_equal([sorted(c) for c in list(nx.cliques_containing_node(G, [1, 2]).values())],
                      [[[2, 6, 1, 3]], [[2, 6, 1, 3], [2, 6, 4]]])
-        assert_equal(nx.cliques_containing_node(G, [1, 2]),
+        result = nx.cliques_containing_node(G, [1, 2])
+        for k, v in result.items():
+            result[k] = sorted(v)
+        assert_equal(result,
                      {1: [[2, 6, 1, 3]], 2: [[2, 6, 1, 3], [2, 6, 4]]})
         assert_equal(nx.cliques_containing_node(G, 1),
                      [[2, 6, 1, 3]])
-        assert_equal(nx.cliques_containing_node(G, 2),
-                     [[2, 6, 1, 3], [2, 6, 4]])
-        assert_equal(nx.cliques_containing_node(G, 2, cliques=self.cl),
-                     [[2, 6, 1, 3], [2, 6, 4]])
+        expected = [{2, 6, 1, 3}, {2, 6, 4}]
+        answer = [set(c) for c in nx.cliques_containing_node(G, 2)]
+        assert_in(answer, (expected, list(reversed(expected))))
+
+        answer = [set(c) for c in nx.cliques_containing_node(G, 2, cliques=self.cl)]
+        assert_in(answer, (expected, list(reversed(expected))))
         assert_equal(len(nx.cliques_containing_node(G)), 11)
 
     def test_make_clique_bipartite(self):
diff --git a/networkx/algorithms/tests/test_covering.py b/networkx/algorithms/tests/test_covering.py
index c504d04f..7539847f 100644
--- a/networkx/algorithms/tests/test_covering.py
+++ b/networkx/algorithms/tests/test_covering.py
@@ -4,7 +4,7 @@
 #    All rights reserved.
 #    BSD license.
 
-from nose.tools import assert_equal, assert_true, assert_false
+from nose.tools import assert_equal, assert_true, assert_false, assert_in
 import networkx as nx
 
 
@@ -23,8 +23,7 @@ class TestMinEdgeCover:
     def test_graph_single_edge(self):
         G = nx.Graph()
         G.add_edge(0, 1)
-        assert_equal(nx.min_edge_cover(G),
-                     {(0, 1)})
+        assert_in(nx.min_edge_cover(G), ({(0, 1)}, {(1, 0)}))
 
     def test_bipartite_explicit(self):
         G = nx.Graph()
diff --git a/networkx/algorithms/tests/test_cycles.py b/networkx/algorithms/tests/test_cycles.py
index 5585041c..df5b3543 100644
--- a/networkx/algorithms/tests/test_cycles.py
+++ b/networkx/algorithms/tests/test_cycles.py
@@ -300,11 +300,11 @@ class TestMinimumCycles(object):
 
     def test_unweighted_diamond(self):
         mcb = minimum_cycle_basis(self.diamond_graph)
-        assert_basis_equal(mcb, [[1, 2, 4], [2, 3, 4]])
+        assert_basis_equal([sorted(c) for c in mcb], [[1, 2, 4], [2, 3, 4]])
 
     def test_weighted_diamond(self):
         mcb = minimum_cycle_basis(self.diamond_graph, weight='weight')
-        assert_basis_equal(mcb, [[1, 2, 4], [1, 2, 3, 4]])
+        assert_basis_equal([sorted(c) for c in mcb], [[1, 2, 4], [1, 2, 3, 4]])
 
     def test_dimensionality(self):
         # checks |MCB|=|E|-|V|+|NC|
diff --git a/networkx/algorithms/tests/test_matching.py b/networkx/algorithms/tests/test_matching.py
index 00faca20..5eeec4f7 100644
--- a/networkx/algorithms/tests/test_matching.py
+++ b/networkx/algorithms/tests/test_matching.py
@@ -118,8 +118,10 @@ class TestMaxWeightMatching(object):
         G.add_weighted_edges_from([(1, 2, 9), (1, 3, 9), (2, 3, 10),
                                    (2, 4, 8), (3, 5, 8), (4, 5, 10),
                                    (5, 6, 6)])
-        assert_equal(nx.max_weight_matching(G),
-                     matching_dict_to_set({1: 3, 2: 4, 3: 1, 4: 2, 5: 6, 6: 5}))
+        dict_format = {1: 3, 2: 4, 3: 1, 4: 2, 5: 6, 6: 5}
+        expected = {frozenset(e) for e in matching_dict_to_set(dict_format)}
+        answer = {frozenset(e) for e in nx.max_weight_matching(G)}
+        assert_equal(answer, expected)
 
     def test_nested_s_blossom_relabel(self):
         """Create S-blossom, relabel as S, include in nested S-blossom:"""
diff --git a/networkx/algorithms/tests/test_planar_drawing.py b/networkx/algorithms/tests/test_planar_drawing.py
index f52a6244..8a4c1168 100644
--- a/networkx/algorithms/tests/test_planar_drawing.py
+++ b/networkx/algorithms/tests/test_planar_drawing.py
@@ -67,7 +67,7 @@ def test_multiple_component_graph2():
 
 @raises(nx.NetworkXException)
 def test_invalid_half_edge():
-    embedding_data = {1: [2, 3], 2: [1, 3], 3: [1, 2], 4: [1, 2, 3]}
+    embedding_data = {1: [2, 3, 4], 2: [1, 3, 4], 3: [1, 2, 4], 4: [1, 2, 3]}
     embedding = nx.PlanarEmbedding()
     embedding.set_data(embedding_data)
     nx.combinatorial_embedding_to_pos(embedding)