Fix tests for deprecate_nonkeyword_argument

Author: alexitkes

pandas/tests/util/test_deprecate_nonkeyword_arguments.py

@@ -16,15 +16,32 @@ def f(a, b=0, c=0, d=0):
     return a + b + c + d
 
 
-def test_two_arguments(x):
+def test_one_arguments():
+    """
+    Check whether no future warning is produced if one
+    positional argument given.
+    """
+    assert f(19) == 19
+
+
+def test_one_and_one_arguments():
+    """
+    Check whether no future warning is produced if one
+    positional argument and one keyword argument are
+    given.
+    """
+    assert f(19, d=6) == 25
+
+
+def test_two_arguments():
     """
     Check whether no future warning is produced if two
     positional arguments given.
     """
     assert f(1, 5) == 6
 
 
-def test_two_and_two_arguments(x):
+def test_two_and_two_arguments():
     """
     Check whether no future warning is produced if two
     positional arguments and two keyword arguments are
@@ -33,7 +50,16 @@ def test_two_and_two_arguments(x):
     assert f(1, 3, c=3, d=5) == 12
 
 
-def test_four_arguments(x):
+def test_three_arguments():
+    """
+    Check whether a future warning is produced if four
+    positional arguments given.
+    """
+    with tm.assert_produces_warning(FutureWarning):
+        assert f(6, 3, 3) == 12
+
+
+def test_four_arguments():
     """
     Check whether a future warning is produced if four
     positional arguments given.