TST: correct constructor in extension array tests + rename to _from_sequence (#20746)

Author: jorisvandenbossche

pandas/core/arrays/base.py

@@ -27,7 +27,7 @@ class ExtensionArray(object):
     The interface includes the following abstract methods that must be
     implemented by subclasses:
 
-    * _constructor_from_sequence
+    * _from_sequence
     * _from_factorized
     * __getitem__
     * __len__
@@ -78,7 +78,7 @@ class ExtensionArray(object):
     # Constructors
     # ------------------------------------------------------------------------
     @classmethod
-    def _constructor_from_sequence(cls, scalars):
+    def _from_sequence(cls, scalars):
         """Construct a new ExtensionArray from a sequence of scalars.
 
         Parameters
@@ -365,7 +365,7 @@ def fillna(self, value=None, method=None, limit=None):
                 func = pad_1d if method == 'pad' else backfill_1d
                 new_values = func(self.astype(object), limit=limit,
                                   mask=mask)
-                new_values = self._constructor_from_sequence(new_values)
+                new_values = self._from_sequence(new_values)
             else:
                 # fill with value
                 new_values = self.copy()
@@ -384,7 +384,7 @@ def unique(self):
         from pandas import unique
 
         uniques = unique(self.astype(object))
-        return self._constructor_from_sequence(uniques)
+        return self._from_sequence(uniques)
 
     def _values_for_factorize(self):
         # type: () -> Tuple[ndarray, Any]

pandas/core/arrays/categorical.py

@@ -422,7 +422,7 @@ def _constructor(self):
         return Categorical
 
     @classmethod
-    def _constructor_from_sequence(cls, scalars):
+    def _from_sequence(cls, scalars):
         return Categorical(scalars)
 
     def copy(self):

pandas/tests/extension/base/constructors.py

@@ -11,7 +11,7 @@ class BaseConstructorsTests(BaseExtensionTests):
 
     def test_array_from_scalars(self, data):
         scalars = [data[0], data[1], data[2]]
-        result = data._constructor_from_sequence(scalars)
+        result = data._from_sequence(scalars)
         assert isinstance(result, type(data))
 
     def test_series_constructor(self, data):

pandas/tests/extension/base/getitem.py

@@ -145,7 +145,7 @@ def test_take_series(self, data):
         s = pd.Series(data)
         result = s.take([0, -1])
         expected = pd.Series(
-            data._constructor_from_sequence([data[0], data[len(data) - 1]]),
+            data._from_sequence([data[0], data[len(data) - 1]]),
             index=[0, len(data) - 1])
         self.assert_series_equal(result, expected)
 
@@ -158,12 +158,11 @@ def test_reindex(self, data, na_value):
         n = len(data)
         result = s.reindex([-1, 0, n])
         expected = pd.Series(
-            data._constructor_from_sequence([na_value, data[0], na_value]),
+            data._from_sequence([na_value, data[0], na_value]),
             index=[-1, 0, n])
         self.assert_series_equal(result, expected)
 
         result = s.reindex([n, n + 1])
-        expected = pd.Series(
-            data._constructor_from_sequence([na_value, na_value]),
-            index=[n, n + 1])
+        expected = pd.Series(data._from_sequence([na_value, na_value]),
+                             index=[n, n + 1])
         self.assert_series_equal(result, expected)

pandas/tests/extension/base/methods.py

@@ -76,7 +76,7 @@ def test_sort_values_frame(self, data_for_sorting, ascending):
     @pytest.mark.parametrize('box', [pd.Series, lambda x: x])
     @pytest.mark.parametrize('method', [lambda x: x.unique(), pd.unique])
     def test_unique(self, data, box, method):
-        duplicated = box(data._constructor_from_sequence([data[0], data[0]]))
+        duplicated = box(data._from_sequence([data[0], data[0]]))
 
         result = method(duplicated)
 

pandas/tests/extension/base/missing.py

@@ -70,7 +70,8 @@ def test_fillna_series(self, data_missing):
         ser = pd.Series(data_missing)
 
         result = ser.fillna(fill_value)
-        expected = pd.Series(type(data_missing)([fill_value, fill_value]))
+        expected = pd.Series(
+            data_missing._from_sequence([fill_value, fill_value]))
         self.assert_series_equal(result, expected)
 
         # Fill with a series
@@ -89,7 +90,8 @@ def test_fillna_series_method(self, data_missing, method):
             data_missing = type(data_missing)(data_missing[::-1])
 
         result = pd.Series(data_missing).fillna(method=method)
-        expected = pd.Series(type(data_missing)([fill_value, fill_value]))
+        expected = pd.Series(
+            data_missing._from_sequence([fill_value, fill_value]))
 
         self.assert_series_equal(result, expected)
 
@@ -102,7 +104,7 @@ def test_fillna_frame(self, data_missing):
         }).fillna(fill_value)
 
         expected = pd.DataFrame({
-            "A": type(data_missing)([fill_value, fill_value]),
+            "A": data_missing._from_sequence([fill_value, fill_value]),
             "B": [1, 2],
         })
 

pandas/tests/extension/base/reshaping.py

@@ -47,8 +47,8 @@ def test_align(self, data, na_value):
         r1, r2 = pd.Series(a).align(pd.Series(b, index=[1, 2, 3]))
 
         # Assumes that the ctor can take a list of scalars of the type
-        e1 = pd.Series(type(data)(list(a) + [na_value]))
-        e2 = pd.Series(type(data)([na_value] + list(b)))
+        e1 = pd.Series(data._from_sequence(list(a) + [na_value]))
+        e2 = pd.Series(data._from_sequence([na_value] + list(b)))
         self.assert_series_equal(r1, e1)
         self.assert_series_equal(r2, e2)
 
@@ -60,8 +60,8 @@ def test_align_frame(self, data, na_value):
         )
 
         # Assumes that the ctor can take a list of scalars of the type
-        e1 = pd.DataFrame({'A': type(data)(list(a) + [na_value])})
-        e2 = pd.DataFrame({'A': type(data)([na_value] + list(b))})
+        e1 = pd.DataFrame({'A': data._from_sequence(list(a) + [na_value])})
+        e2 = pd.DataFrame({'A': data._from_sequence([na_value] + list(b))})
         self.assert_frame_equal(r1, e1)
         self.assert_frame_equal(r2, e2)
 
@@ -71,9 +71,8 @@ def test_align_series_frame(self, data, na_value):
         df = pd.DataFrame({"col": np.arange(len(ser) + 1)})
         r1, r2 = ser.align(df)
 
-        e1 = pd.Series(
-            data._constructor_from_sequence(list(data) + [na_value]),
-            name=ser.name)
+        e1 = pd.Series(data._from_sequence(list(data) + [na_value]),
+                       name=ser.name)
 
         self.assert_series_equal(r1, e1)
         self.assert_frame_equal(r2, df)
@@ -105,14 +104,13 @@ def test_merge(self, data, na_value):
         res = pd.merge(df1, df2)
         exp = pd.DataFrame(
             {'int1': [1, 1, 2], 'int2': [1, 2, 3], 'key': [0, 0, 1],
-             'ext': data._constructor_from_sequence(
-                 [data[0], data[0], data[1]])})
+             'ext': data._from_sequence([data[0], data[0], data[1]])})
         self.assert_frame_equal(res, exp[['ext', 'int1', 'key', 'int2']])
 
         res = pd.merge(df1, df2, how='outer')
         exp = pd.DataFrame(
             {'int1': [1, 1, 2, 3, np.nan], 'int2': [1, 2, 3, np.nan, 4],
              'key': [0, 0, 1, 2, 3],
-             'ext': data._constructor_from_sequence(
+             'ext': data._from_sequence(
                  [data[0], data[0], data[1], data[2], na_value])})
         self.assert_frame_equal(res, exp[['ext', 'int1', 'key', 'int2']])

pandas/tests/extension/base/setitem.py

@@ -27,7 +27,7 @@ def test_setitem_sequence_mismatched_length_raises(self, data, as_array):
         ser = pd.Series(data)
         value = [data[0]]
         if as_array:
-            value = type(data)(value)
+            value = data._from_sequence(value)
 
         xpr = 'cannot set using a {} indexer with a different length'
         with tm.assert_raises_regex(ValueError, xpr.format('list-like')):

pandas/tests/extension/decimal/array.py

@@ -36,7 +36,7 @@ def __init__(self, values):
         self._items = self._data = self.data = self.values
 
     @classmethod
-    def _constructor_from_sequence(cls, scalars):
+    def _from_sequence(cls, scalars):
         return cls(scalars)
 
     @classmethod

pandas/tests/extension/json/array.py

@@ -34,7 +34,7 @@ def __init__(self, values):
         self.data = values
 
     @classmethod
-    def _constructor_from_sequence(cls, scalars):
+    def _from_sequence(cls, scalars):
         return cls(scalars)
 
     @classmethod
@@ -45,9 +45,7 @@ def __getitem__(self, item):
         if isinstance(item, numbers.Integral):
             return self.data[item]
         elif isinstance(item, np.ndarray) and item.dtype == 'bool':
-            return self._constructor_from_sequence([
-                x for x, m in zip(self, item) if m
-            ])
+            return self._from_sequence([x for x, m in zip(self, item) if m])
         elif isinstance(item, collections.Iterable):
             # fancy indexing
             return type(self)([self.data[i] for i in item])
@@ -95,7 +93,7 @@ def take(self, indexer, allow_fill=True, fill_value=None):
         except IndexError:
             raise IndexError("Index is out of bounds or cannot do a "
                              "non-empty take from an empty array.")
-        return self._constructor_from_sequence(output)
+        return self._from_sequence(output)
 
     def copy(self, deep=False):
         return type(self)(self.data[:])