TST: tests for needs-test issues #12857 #12689 (#30327)

Author: jbrockmendel

Diff for: pandas/tests/frame/test_arithmetic.py

@@ -16,6 +16,13 @@
 class TestFrameComparisons:
     # Specifically _not_ flex-comparisons
 
+    def test_frame_in_list(self):
+        # GH#12689 this should raise at the DataFrame level, not blocks
+        df = pd.DataFrame(np.random.randn(6, 4), columns=list("ABCD"))
+        msg = "The truth value of a DataFrame is ambiguous"
+        with pytest.raises(ValueError, match=msg):
+            df in [None]
+
     def test_comparison_invalid(self):
         def check(df, df2):
 

Diff for: pandas/tests/frame/test_constructors.py

@@ -43,6 +43,19 @@
 
 
 class TestDataFrameConstructors:
+    def test_series_with_name_not_matching_column(self):
+        # GH#9232
+        x = pd.Series(range(5), name=1)
+        y = pd.Series(range(5), name=0)
+
+        result = pd.DataFrame(x, columns=[0])
+        expected = pd.DataFrame([], columns=[0])
+        tm.assert_frame_equal(result, expected)
+
+        result = pd.DataFrame(y, columns=[1])
+        expected = pd.DataFrame([], columns=[1])
+        tm.assert_frame_equal(result, expected)
+
     @pytest.mark.parametrize(
         "constructor",
         [

Diff for: pandas/tests/io/parser/test_header.py

@@ -540,3 +540,34 @@ def test_multi_index_unnamed(all_parsers, index_col, columns):
         columns = MultiIndex.from_tuples(zip(exp_columns, ["0", "1"]))
         expected = DataFrame([[2, 3], [4, 5]], columns=columns)
         tm.assert_frame_equal(result, expected)
+
+
+def test_read_csv_multiindex_columns(all_parsers):
+    # GH#6051
+    parser = all_parsers
+
+    s1 = "Male, Male, Male, Female, Female\nR, R, L, R, R\n.86, .67, .88, .78, .81"
+    s2 = (
+        "Male, Male, Male, Female, Female\n"
+        "R, R, L, R, R\n"
+        ".86, .67, .88, .78, .81\n"
+        ".86, .67, .88, .78, .82"
+    )
+
+    mi = MultiIndex.from_tuples(
+        [
+            ("Male", "R"),
+            (" Male", " R"),
+            (" Male", " L"),
+            (" Female", " R"),
+            (" Female", " R.1"),
+        ]
+    )
+    expected = DataFrame(
+        [[0.86, 0.67, 0.88, 0.78, 0.81], [0.86, 0.67, 0.88, 0.78, 0.82]], columns=mi
+    )
+
+    df1 = parser.read_csv(StringIO(s1), header=[0, 1])
+    tm.assert_frame_equal(df1, expected.iloc[:1])
+    df2 = parser.read_csv(StringIO(s2), header=[0, 1])
+    tm.assert_frame_equal(df2, expected)