1 files changed, 108 insertions, 7 deletions
diff --git a/networkx/drawing/tests/test_layout.py b/networkx/drawing/tests/test_layout.py
index bcd6d236..8366d252 100644
--- a/networkx/drawing/tests/test_layout.py
+++ b/networkx/drawing/tests/test_layout.py
@@ -32,14 +32,115 @@ class TestLayout(object):
         vpos=nx.shell_layout(G)
 
     def test_smoke_string(self):
-        G=self.Gs
-        vpos=nx.random_layout(G)
-        vpos=nx.circular_layout(G)
-        vpos=nx.spring_layout(G)
-        vpos=nx.fruchterman_reingold_layout(G)
-        vpos=nx.spectral_layout(G)
-        vpos=nx.shell_layout(G)
+        G = self.Gs
+        vpos = nx.random_layout(G)
+        vpos = nx.circular_layout(G)
+        vpos = nx.spring_layout(G)
+        vpos = nx.fruchterman_reingold_layout(G)
+        vpos = nx.spectral_layout(G)
+        vpos = nx.shell_layout(G)
+
+    def test_empty_graph(self):
+        G=nx.Graph()
+        vpos = nx.random_layout(G)
+        vpos = nx.circular_layout(G)
+        vpos = nx.spring_layout(G)
+        vpos = nx.fruchterman_reingold_layout(G)
+        vpos = nx.shell_layout(G)
+        vpos = nx.spectral_layout(G)
+        # center arg
+        vpos = nx.random_layout(G, scale=2, center=(4,5))
+        vpos = nx.circular_layout(G, scale=2, center=(4,5))
+        vpos = nx.spring_layout(G, scale=2, center=(4,5))
+        vpos = nx.shell_layout(G, scale=2, center=(4,5))
+        vpos = nx.spectral_layout(G, scale=2, center=(4,5))
+
+    def test_single_node(self):
+        G = nx.Graph()
+        G.add_node(0)
+        vpos = nx.random_layout(G)
+        vpos = nx.circular_layout(G)
+        vpos = nx.spring_layout(G)
+        vpos = nx.fruchterman_reingold_layout(G)
+        vpos = nx.shell_layout(G)
+        vpos = nx.spectral_layout(G)
+        # center arg
+        vpos = nx.random_layout(G, scale=2, center=(4,5))
+        vpos = nx.circular_layout(G, scale=2, center=(4,5))
+        vpos = nx.spring_layout(G, scale=2, center=(4,5))
+        vpos = nx.shell_layout(G, scale=2, center=(4,5))
+        vpos = nx.spectral_layout(G, scale=2, center=(4,5))
+
+    def check_scale_and_center(self, pos, scale, center):
+        center = numpy.array(center)
+        low = center - 0.5 * scale
+        hi = center + 0.5 * scale
+        vpos = numpy.array(list(pos.values()))
+        length = vpos.max(0) - vpos.min(0)
+        assert (length <= scale).all()
+        assert (vpos >= low).all()
+        assert (vpos <= hi).all()
+
+    def test_scale_and_center_arg(self):
+        G = nx.complete_graph(9)
+        G.add_node(9)
+        vpos = nx.random_layout(G, scale=2, center=(4,5))
+        self.check_scale_and_center(vpos, scale=2, center=(4,5))
+        vpos = nx.spring_layout(G, scale=2, center=(4,5))
+        self.check_scale_and_center(vpos, scale=2, center=(4,5))
+        vpos = nx.spectral_layout(G, scale=2, center=(4,5))
+        self.check_scale_and_center(vpos, scale=2, center=(4,5))
+        # circular can have twice as big length
+        vpos = nx.circular_layout(G, scale=2, center=(4,5))
+        self.check_scale_and_center(vpos, scale=2*2, center=(4,5))
+        vpos = nx.shell_layout(G, scale=2, center=(4,5))
+        self.check_scale_and_center(vpos, scale=2*2, center=(4,5))
+
+        # check default center and scale
+        vpos = nx.random_layout(G)
+        self.check_scale_and_center(vpos, scale=1, center=(0.5,0.5))
+        vpos = nx.spring_layout(G)
+        self.check_scale_and_center(vpos, scale=1, center=(0.5,0.5))
+        vpos = nx.spectral_layout(G)
+        self.check_scale_and_center(vpos, scale=1, center=(0.5,0.5))
+        vpos = nx.circular_layout(G)
+        self.check_scale_and_center(vpos, scale=2, center=(0,0))
+        vpos = nx.shell_layout(G)
+        self.check_scale_and_center(vpos, scale=2, center=(0,0))
+
+    def test_shell_layout(self):
+        G = nx.complete_graph(9)
+        shells=[[0], [1,2,3,5], [4,6,7,8]]
+        vpos = nx.shell_layout(G, nlist=shells)
+        vpos = nx.shell_layout(G, nlist=shells, scale=2, center=(3,4))
+        shells=[[0,1,2,3,5], [4,6,7,8]]
+        vpos = nx.shell_layout(G, nlist=shells)
+        vpos = nx.shell_layout(G, nlist=shells, scale=2, center=(3,4))
+
+    def test_spring_args(self):
+        G = nx.complete_graph(9)
+        vpos = nx.spring_layout(G, dim=3)
+        assert_equal(vpos[0].shape, (3,))
+        vpos = nx.spring_layout(G, fixed=[0,1], pos={1:(0,0), 2:(1,1)})
+        vpos = nx.spring_layout(G, k=2, fixed=[0,1], pos={1:(0,0), 2:(1,1)})
+        vpos = nx.spring_layout(G, scale=3, center=(2,5))
+        vpos = nx.spring_layout(G, scale=3)
+        vpos = nx.spring_layout(G, center=(2,5))
 
+    def test_spectral_for_small_graphs(self):
+        G = nx.Graph()
+        vpos = nx.spectral_layout(G)
+        vpos = nx.spectral_layout(G, center=(2,3))
+        G.add_node(0)
+        vpos = nx.spectral_layout(G)
+        vpos = nx.spectral_layout(G, center=(2,3))
+        G.add_node(1)
+        vpos = nx.spectral_layout(G)
+        vpos = nx.spectral_layout(G, center=(2,3))
+        # 3 nodes should allow eigensolvers to work
+        G.add_node(2)
+        vpos = nx.spectral_layout(G)
+        vpos = nx.spectral_layout(G, center=(2,3))
 
     def test_adjacency_interface_numpy(self):
         A=nx.to_numpy_matrix(self.Gs)