Merge remote-tracking branch 'upstream/master' into as_index_false

Author: rhshadrach

pandas/tests/groupby/test_function.py

@@ -573,6 +573,28 @@ def test_ops_general(op, targop):
     tm.assert_frame_equal(result, expected)
 
 
+def test_ops_not_as_index(reduction_func):
+    # GH 10355
+    # Using as_index=False should not modify grouped column
+
+    if reduction_func in ("nth", "ngroup", "size",):
+        pytest.skip("Skip until behavior is determined (GH #5755)")
+
+    if reduction_func in ("corrwith", "idxmax", "idxmin", "mad", "nunique", "skew",):
+        pytest.xfail(
+            "_GroupBy._python_apply_general incorrectly modifies grouping columns"
+        )
+
+    df = DataFrame(np.random.randint(0, 5, size=(100, 2)), columns=["a", "b"])
+    expected = getattr(df.groupby("a"), reduction_func)().reset_index()
+
+    result = getattr(df.groupby("a", as_index=False), reduction_func)()
+    tm.assert_frame_equal(result, expected)
+
+    result = getattr(df.groupby("a", as_index=False)["b"], reduction_func)()
+    tm.assert_frame_equal(result, expected)
+
+
 def test_max_nan_bug():
     raw = """,Date,app,File
 -04-23,2013-04-23 00:00:00,,log080001.log