Increased code coverage

pydatastructs/graphs/__init__.py

@@ -11,3 +11,9 @@
     AdjacencyList
 )
 __all__.extend(adjacency_list.__all__)
+
+from . import adjacency_matrix
+from .adjacency_matrix import (
+    AdjacencyMatrix
+)
+__all__.extend(adjacency_matrix.__all__)

pydatastructs/graphs/tests/test_adjacency_list.py

@@ -1,5 +1,6 @@
 from pydatastructs.graphs import Graph
 from pydatastructs.utils import AdjacencyListGraphNode
+from pydatastructs.utils.raises_util import raises
 
 def test_adjacency_list():
     v_1 = AdjacencyListGraphNode('v_1', 1)
@@ -32,3 +33,4 @@ def test_adjacency_list():
     g.remove_vertex('v')
     assert g.is_adjacent('v_2', 'v') is False
     assert g.is_adjacent('v_3', 'v') is False
+    assert raises(NotImplementedError, lambda: Graph(implementation=''))

pydatastructs/graphs/tests/test_adjacency_matrix.py

@@ -1,5 +1,7 @@
 from pydatastructs.graphs import Graph
 from pydatastructs.utils import AdjacencyMatrixGraphNode
+from pydatastructs.utils.raises_util import raises
+from pydatastructs.graphs import AdjacencyMatrix
 
 def test_AdjacencyMatrix():
     v_0 = AdjacencyMatrixGraphNode(0, 0)
@@ -19,3 +21,4 @@ def test_AdjacencyMatrix():
     assert neighbors == [v_1]
     g.remove_edge(0, 1)
     assert g.is_adjacent(0, 1) is False
+    assert raises(NotImplementedError, lambda: Graph(implementation=''))