Moves format_kwarg_dictionaries to utils and adds tests

mlxtend/plotting/decision_regions.py

@@ -9,7 +9,7 @@
 from itertools import cycle
 import matplotlib.pyplot as plt
 import numpy as np
-from ..utils import check_Xy
+from ..utils import check_Xy, format_kwarg_dictionaries
 import warnings
 
 
@@ -215,7 +215,7 @@ def plot_decision_regions(X, y, clf,
     # Plot decisoin region
     # Make sure contourf_kwargs has backwards compatible defaults
     contourf_kwargs_default = {'alpha': 0.3, 'antialiased': True}
-    contourf_kwargs = format_plotting_kwargs(
+    contourf_kwargs = format_kwarg_dictionaries(
                         default_kwargs=contourf_kwargs_default,
                         user_kwargs=contourf_kwargs,
                         protected_keys=['colors', 'levels'])
@@ -229,7 +229,7 @@ def plot_decision_regions(X, y, clf,
     # Scatter training data samples
     # Make sure scatter_kwargs has backwards compatible defaults
     scatter_kwargs_default = {'alpha': 0.8, 'edgecolor': 'black'}
-    scatter_kwargs = format_plotting_kwargs(
+    scatter_kwargs = format_kwarg_dictionaries(
                         default_kwargs=scatter_kwargs_default,
                         user_kwargs=scatter_kwargs,
                         protected_keys=['c', 'marker', 'label'])
@@ -288,7 +288,7 @@ def plot_decision_regions(X, y, clf,
                                       'linewidths': 1,
                                       'marker': 'o',
                                       's': 80}
-        scatter_highlight_kwargs = format_plotting_kwargs(
+        scatter_highlight_kwargs = format_kwarg_dictionaries(
                                     default_kwargs=scatter_highlight_defaults,
                                     user_kwargs=scatter_highlight_kwargs)
         ax.scatter(x_data,
@@ -304,36 +304,3 @@ def plot_decision_regions(X, y, clf,
                       framealpha=0.3, scatterpoints=1, loc=legend)
 
     return ax
-
-
-def format_plotting_kwargs(default_kwargs=None, user_kwargs=None,
-                           protected_keys=None):
-    """Function to combine default and user specified plotting kwargs
-
-    Parameters
-    ----------
-    default_kwargs : dict, optional
-        Default kwargs (default is None).
-    user_kwargs : dict, optional
-        User specified kwargs (default is None).
-    protected_keys : array_like, optional
-        Sequence of keys to be removed from the returned dictionary
-        (default is None).
-
-    Returns
-    -------
-    plotting_dict : dict
-        Formatted plotting dictionary.
-    """
-    plotting_dict = {}
-    for d in [default_kwargs, user_kwargs]:
-        if not isinstance(d, (dict, type(None))):
-            raise TypeError('d must be of type dict or None, but '
-                            'got {} instead'.format(type(d)))
-        if d is not None:
-            plotting_dict.update(d)
-    if protected_keys is not None:
-        for key in protected_keys:
-            plotting_dict.pop(key, None)
-
-    return plotting_dict

mlxtend/utils/__init__.py

@@ -6,6 +6,7 @@
 
 from .counter import Counter
 from .testing import assert_raises
-from .checking import check_Xy
+from .checking import check_Xy, format_kwarg_dictionaries
 
-__all__ = ["Counter", "assert_raises", "check_Xy"]
+__all__ = ["Counter", "assert_raises", "check_Xy",
+           "format_kwarg_dictionaries"]

mlxtend/utils/checking.py

@@ -36,3 +36,36 @@ def check_Xy(X, y, y_int=True):
     if y.shape[0] != X.shape[0]:
         raise ValueError('y and X must contain the same number of samples. '
                          'Got y: %d, X: %d' % (y.shape[0], X.shape[0]))
+
+
+def format_kwarg_dictionaries(default_kwargs=None, user_kwargs=None,
+                              protected_keys=None):
+    """Function to combine default and user specified kwargs dictionaries
+
+    Parameters
+    ----------
+    default_kwargs : dict, optional
+        Default kwargs (default is None).
+    user_kwargs : dict, optional
+        User specified kwargs (default is None).
+    protected_keys : array_like, optional
+        Sequence of keys to be removed from the returned dictionary
+        (default is None).
+
+    Returns
+    -------
+    formatted_kwargs : dict
+        Formatted kwargs dictionary.
+    """
+    formatted_kwargs = {}
+    for d in [default_kwargs, user_kwargs]:
+        if not isinstance(d, (dict, type(None))):
+            raise TypeError('d must be of type dict or None, but '
+                            'got {} instead'.format(type(d)))
+        if d is not None:
+            formatted_kwargs.update(d)
+    if protected_keys is not None:
+        for key in protected_keys:
+            formatted_kwargs.pop(key, None)
+
+    return formatted_kwargs

mlxtend/utils/tests/test_checking_inputs.py

@@ -5,20 +5,24 @@
 # License: BSD 3 clause
 
 from mlxtend.utils import assert_raises
-from mlxtend.utils import check_Xy
+from mlxtend.utils import check_Xy, format_kwarg_dictionaries
 import numpy as np
 import sys
 import os
 
 y = np.array([1, 2, 3, 4])
 X = np.array([[1., 2.], [3., 4.], [5., 6.], [7., 8.]])
 
+d_default = {'key1': 1, 'key2': 2}
+d_user = {'key3': 3, 'key4': 4}
+protected_keys = ['key1', 'key4']
 
-def test_ok():
+
+def test_check_Xy_ok():
     check_Xy(X, y)
 
 
-def test_invalid_type_X():
+def test_check_Xy_invalid_type_X():
     expect = "X must be a NumPy array. Found <class 'list'>"
     if (sys.version_info < (3, 0)):
         expect = expect.replace('class', 'type')
@@ -29,15 +33,15 @@ def test_invalid_type_X():
                   y)
 
 
-def test_float16_X():
+def test_check_Xy_float16_X():
     check_Xy(X.astype(np.float16), y)
 
 
-def test_float16_y():
+def test_check_Xy_float16_y():
     check_Xy(X, y.astype(np.int16))
 
 
-def test_invalid_type_y():
+def test_check_Xy_invalid_type_y():
     expect = "y must be a NumPy array. Found <class 'list'>"
     if (sys.version_info < (3, 0)):
         expect = expect.replace('class', 'type')
@@ -48,15 +52,15 @@ def test_invalid_type_y():
                   [1, 2, 3, 4])
 
 
-def test_invalid_dtype_X():
+def test_check_Xy_invalid_dtype_X():
     assert_raises(ValueError,
                   'X must be an integer or float array. Found object.',
                   check_Xy,
                   X.astype('object'),
                   y)
 
 
-def test_invalid_dtype_y():
+def test_check_Xy_invalid_dtype_y():
 
     if (sys.version_info > (3, 0)):
         expect = ('y must be an integer array. Found <U1. '
@@ -71,7 +75,7 @@ def test_invalid_dtype_y():
                   np.array(['a', 'b', 'c', 'd']))
 
 
-def test_invalid_dim_y():
+def test_check_Xy_invalid_dim_y():
     if sys.version_info[:2] == (2, 7) and os.name == 'nt':
         s = 'y must be a 1D array. Found (4L, 2L)'
     else:
@@ -83,7 +87,7 @@ def test_invalid_dim_y():
                   X.astype(np.integer))
 
 
-def test_invalid_dim_X():
+def test_check_Xy_invalid_dim_X():
     if sys.version_info[:2] == (2, 7) and os.name == 'nt':
         s = 'X must be a 2D array. Found (4L,)'
     else:
@@ -95,7 +99,7 @@ def test_invalid_dim_X():
                   y)
 
 
-def test_unequal_length_X():
+def test_check_Xy_unequal_length_X():
     assert_raises(ValueError,
                   ('y and X must contain the same number of samples. '
                    'Got y: 4, X: 3'),
@@ -104,10 +108,56 @@ def test_unequal_length_X():
                   y)
 
 
-def test_unequal_length_y():
+def test_check_Xy_unequal_length_y():
     assert_raises(ValueError,
                   ('y and X must contain the same number of samples. '
                    'Got y: 3, X: 4'),
                   check_Xy,
                   X,
                   y[1:])
+
+
+def test_format_kwarg_dictionaries_defaults_empty():
+    empty = format_kwarg_dictionaries()
+    assert isinstance(empty, dict)
+    assert len(empty) == 0
+
+
+def test_format_kwarg_dictionaries_protected_keys():
+    formatted_kwargs = format_kwarg_dictionaries(
+                            default_kwargs=d_default,
+                            user_kwargs=d_user,
+                            protected_keys=protected_keys)
+
+    for key in protected_keys:
+        assert key not in formatted_kwargs
+
+
+def test_format_kwarg_dictionaries_no_default_kwargs():
+    formatted_kwargs = format_kwarg_dictionaries(user_kwargs=d_user)
+    assert formatted_kwargs == d_user
+
+
+def test_format_kwarg_dictionaries_no_user_kwargs():
+    formatted_kwargs = format_kwarg_dictionaries(default_kwargs=d_default)
+    assert formatted_kwargs == d_default
+
+
+def test_format_kwarg_dictionaries_default_kwargs_invalid_type():
+    invalid_kwargs = 'not a dictionary'
+    message = ('d must be of type dict or None, but got '
+               '{} instead'.format(type(invalid_kwargs)))
+    assert_raises(TypeError,
+                  message,
+                  format_kwarg_dictionaries,
+                  default_kwargs=invalid_kwargs)
+
+
+def test_format_kwarg_dictionaries_user_kwargs_invalid_type():
+    invalid_kwargs = 'not a dictionary'
+    message = ('d must be of type dict or None, but got '
+               '{} instead'.format(type(invalid_kwargs)))
+    assert_raises(TypeError,
+                  message,
+                  format_kwarg_dictionaries,
+                  user_kwargs=invalid_kwargs)