Add tests for subgraphs without copy for [bi]components.

This brings coverage to 100% in all modules of the components package.

2 files changed, 78 insertions, 43 deletions

diff --git a/networkx/algorithms/components/tests/test_biconnected.py b/networkx/algorithms/components/tests/test_biconnected.py
index b1b23ebe..ede2d12a 100644
--- a/networkx/algorithms/components/tests/test_biconnected.py
+++ b/networkx/algorithms/components/tests/test_biconnected.py
@@ -87,6 +87,21 @@ def test_biconnected_component_subgraphs_cycle():
         assert_equal(g1[1][3]['eattr'],'blue')
         assert_equal(G[1][3]['eattr'],'red')
 
+def test_biconnected_component_subgraphs_no_copy():
+    G = nx.Graph()
+    G.add_edge(1, 2, eattr='red') # test attributes copied to subgraphs
+    G.node[1]['nattr'] = 'blue'
+    G.graph['gattr'] = 'green'
+    ccs = list(nx.biconnected_component_subgraphs(G, copy=False))
+    assert_equal(len(ccs), 1)
+    sg = ccs[0]
+    assert_equal(sg[1][2]['eattr'], 'red')
+    assert_equal(sg.node[1]['nattr'], 'blue')
+    assert_equal(sg.graph['gattr'], 'green')
+    sg[1][2]['eattr'] = 'blue'
+    assert_equal(G[1][2]['eattr'], 'blue')
+    assert_equal(sg[1][2]['eattr'], 'blue')
+
 
 def test_biconnected_components1():
     # graph example from
diff --git a/networkx/algorithms/components/tests/test_connected.py b/networkx/algorithms/components/tests/test_connected.py
index 72897f76..24eeabcb 100644
--- a/networkx/algorithms/components/tests/test_connected.py
+++ b/networkx/algorithms/components/tests/test_connected.py
@@ -7,66 +7,86 @@ from networkx import NetworkXError,NetworkXNotImplemented
 class TestConnected:
 
     def setUp(self):
-        G1=cnlti(nx.grid_2d_graph(2,2),first_label=0,ordering="sorted")
-        G2=cnlti(nx.lollipop_graph(3,3),first_label=4,ordering="sorted")
-        G3=cnlti(nx.house_graph(),first_label=10,ordering="sorted")
-        self.G=nx.union(G1,G2)
-        self.G=nx.union(self.G,G3)
-        self.DG=nx.DiGraph([(1,2),(1,3),(2,3)])
-        self.grid=cnlti(nx.grid_2d_graph(4,4),first_label=1)
+        G1 = cnlti(nx.grid_2d_graph(2, 2), first_label=0, ordering="sorted")
+        G2 = cnlti(nx.lollipop_graph(3, 3), first_label=4, ordering="sorted")
+        G3 = cnlti(nx.house_graph(), first_label=10, ordering="sorted")
+        self.G = nx.union(G1, G2)
+        self.G = nx.union(self.G, G3)
+        self.DG = nx.DiGraph([(1, 2), (1, 3), (2, 3)])
+        self.grid = cnlti(nx.grid_2d_graph(4, 4), first_label=1)
 
     def test_connected_components(self):
-        cc=nx.connected_components
-        G=self.G
-        C=[[0, 1, 2, 3], [4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14]]
-        assert_equal(sorted([sorted(g) for g in cc(G)]),sorted(C))
+        cc = nx.connected_components
+        G = self.G
+        C = {
+            frozenset([0, 1, 2, 3]),
+            frozenset([4, 5, 6, 7, 8, 9]),
+            frozenset([10, 11, 12, 13, 14])
+        }
+        assert_equal({frozenset(g) for g in cc(G)}, C)
 
     def test_number_connected_components(self):
-        ncc=nx.number_connected_components
-        assert_equal(ncc(self.G),3)
+        ncc = nx.number_connected_components
+        assert_equal(ncc(self.G), 3)
 
     def test_number_connected_components2(self):
-        ncc=nx.number_connected_components
-        assert_equal(ncc(self.grid),1)
+        ncc = nx.number_connected_components
+        assert_equal(ncc(self.grid), 1)
 
     def test_connected_components2(self):
-        cc=nx.connected_components
-        G=self.grid
-        C=[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]]
-        assert_equal(sorted([sorted(g) for g in cc(G)]),sorted(C))
+        cc = nx.connected_components
+        G = self.grid
+        C = {frozenset([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16])}
+        assert_equal({frozenset(g) for g in cc(G)}, C)
 
     def test_node_connected_components(self):
-        ncc=nx.node_connected_component
-        G=self.grid
-        C=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]
-        assert_equal(sorted(ncc(G,1)),sorted(C))
+        ncc = nx.node_connected_component
+        G = self.grid
+        C = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
+        assert_equal(ncc(G, 1), C)
 
     def test_connected_component_subgraphs(self):
         G=self.grid
-        G.add_edge(1,2,eattr='red') # test attributes copied to subgraphs
-        G.node[1]['nattr']='blue'
-        G.graph['gattr']='green'
-        ccs=list(nx.connected_component_subgraphs(G))
-        assert_equal(len(ccs),1)
-        sg=ccs[0]
-        assert_equal(sorted(sg.nodes()),list(range(1,17)))
-        assert_equal(sg[1][2]['eattr'],'red')
-        assert_equal(sg.node[1]['nattr'],'blue')
-        assert_equal(sg.graph['gattr'],'green')
-        sg[1][2]['eattr']='blue'
-        assert_equal(G[1][2]['eattr'],'red')
-        assert_equal(sg[1][2]['eattr'],'blue')
+        G.add_edge(1, 2, eattr='red') # test attributes copied to subgraphs
+        G.node[1]['nattr'] = 'blue'
+        G.graph['gattr'] = 'green'
+        ccs = list(nx.connected_component_subgraphs(G))
+        assert_equal(len(ccs), 1)
+        sg = ccs[0]
+        assert_equal(sorted(sg), list(range(1,17)))
+        assert_equal(sg[1][2]['eattr'], 'red')
+        assert_equal(sg.node[1]['nattr'], 'blue')
+        assert_equal(sg.graph['gattr'], 'green')
+        sg[1][2]['eattr'] = 'blue'
+        assert_equal(G[1][2]['eattr'], 'red')
+        assert_equal(sg[1][2]['eattr'], 'blue')
 
+    def test_connected_component_subgraphs_no_copy(self):
+        G=self.grid
+        G.add_edge(1, 2, eattr='red') # test attributes copied to subgraphs
+        G.node[1]['nattr'] = 'blue'
+        G.graph['gattr'] = 'green'
+        ccs = list(nx.connected_component_subgraphs(G, copy=False))
+        assert_equal(len(ccs), 1)
+        sg = ccs[0]
+        assert_equal(sorted(sg), list(range(1,17)))
+        assert_equal(sg[1][2]['eattr'], 'red')
+        assert_equal(sg.node[1]['nattr'], 'blue')
+        assert_equal(sg.graph['gattr'], 'green')
+        sg[1][2]['eattr'] = 'blue'
+        assert_equal(G[1][2]['eattr'], 'blue')
+        assert_equal(sg[1][2]['eattr'], 'blue')
 
     def test_is_connected(self):
         assert_true(nx.is_connected(self.grid))
-        G=nx.Graph()
-        G.add_nodes_from([1,2])
+        G = nx.Graph()
+        G.add_nodes_from([1, 2])
         assert_false(nx.is_connected(G))
 
     def test_connected_raise(self):
-        assert_raises(NetworkXNotImplemented,nx.connected_components,self.DG)
-        assert_raises(NetworkXNotImplemented,nx.number_connected_components,self.DG)
-        assert_raises(NetworkXNotImplemented,nx.connected_component_subgraphs,self.DG)
-        assert_raises(NetworkXNotImplemented,nx.node_connected_component,self.DG,1)
-        assert_raises(NetworkXNotImplemented,nx.is_connected,self.DG)
+        assert_raises(NetworkXNotImplemented, nx.connected_components, self.DG)
+        assert_raises(NetworkXNotImplemented, nx.number_connected_components, self.DG)
+        assert_raises(NetworkXNotImplemented, nx.connected_component_subgraphs, self.DG)
+        assert_raises(NetworkXNotImplemented, nx.node_connected_component, self.DG,1)
+        assert_raises(NetworkXNotImplemented, nx.is_connected, self.DG)
+        assert_raises(nx.NetworkXPointlessConcept, nx.is_connected, nx.Graph())