Test cases for check_bipartite_graph_bfs (#10688)

* [ADD] tests for check_bipartite_graph_bfs

* linter fix?

* linter fix

* [ADD] more test cases check_bipartite_graph_bfs

* doctest fixes. Forgot to add 'Traceback...'

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* missed a Traceback

* Update check_bipartite_graph_bfs.py

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

graphs/check_bipartite_graph_bfs.py

@@ -10,6 +10,48 @@ from queue import Queue
 
 
 def check_bipartite(graph):
+    """
+    >>> check_bipartite({})
+    True
+    >>> check_bipartite({0: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2]})
+    True
+    >>> check_bipartite({0: [1, 2, 3], 1: [0, 2], 2: [0, 1, 3], 3: [0, 2]})
+    False
+    >>> check_bipartite({0: [4], 1: [], 2: [4], 3: [4], 4: [0, 2, 3]})
+    True
+    >>> check_bipartite({0: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2], 4: [0]})
+    False
+    >>> check_bipartite({7: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2], 4: [0]})
+    Traceback (most recent call last):
+        ...
+    KeyError: 0
+    >>> check_bipartite({0: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2], 9: [0]})
+    Traceback (most recent call last):
+        ...
+    KeyError: 4
+    >>> check_bipartite({0: [-1, 3], 1: [0, -2]})
+    Traceback (most recent call last):
+        ...
+    IndexError: list index out of range
+    >>> check_bipartite({-1: [0, 2], 0: [-1, 1], 1: [0, 2], 2: [-1, 1]})
+    True
+    >>> check_bipartite({0.9: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2]})
+    Traceback (most recent call last):
+        ...
+    KeyError: 0
+    >>> check_bipartite({0: [1.0, 3.0], 1.0: [0, 2.0], 2.0: [1.0, 3.0], 3.0: [0, 2.0]})
+    Traceback (most recent call last):
+        ...
+    TypeError: list indices must be integers or slices, not float
+    >>> check_bipartite({"a": [1, 3], "b": [0, 2], "c": [1, 3], "d": [0, 2]})
+    Traceback (most recent call last):
+        ...
+    KeyError: 0
+    >>> check_bipartite({0: ["b", "d"], 1: ["a", "c"], 2: ["b", "d"], 3: ["a", "c"]})
+    Traceback (most recent call last):
+        ...
+    TypeError: list indices must be integers or slices, not str
+    """
     queue = Queue()
     visited = [False] * len(graph)
     color = [-1] * len(graph)
@@ -45,3 +87,6 @@ def check_bipartite(graph):
 if __name__ == "__main__":
     # Adjacency List of graph
     print(check_bipartite({0: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2]}))
+    import doctest
+
+    doctest.testmod()