TST: read_csv to nullable int dtype (pandas-dev#25472)

Author: alexreg

pandas/tests/io/parser/dtypes/test_dtypes_basic.py

@@ -314,3 +314,23 @@ def test_dtype_multi_index(all_parsers):
     )
 
     tm.assert_frame_equal(result, expected)
+
+
+def test_nullable_int_dtype(all_parsers, any_int_ea_dtype):
+    # GH 25472
+    parser = all_parsers
+    dtype = any_int_ea_dtype
+
+    data = """a,b,c
+,3,5
+1,,6
+2,4,"""
+    expected = DataFrame(
+        {
+            "a": pd.array([pd.NA, 1, 2], dtype=dtype),
+            "b": pd.array([3, pd.NA, 4], dtype=dtype),
+            "c": pd.array([5, 6, pd.NA], dtype=dtype),
+        }
+    )
+    actual = parser.read_csv(StringIO(data), dtype=dtype)
+    tm.assert_frame_equal(actual, expected)