Fix support for pandas StringDtype columns

CHANGELOG.rst

@@ -1,3 +1,10 @@
+UNRELEASED
+----------
+
+*UNRELEASED*
+
+* `#208 <https://github.com/ESSS/pytest-regressions/issues/208>`__: Fixed support for ``pandas.StringDtype`` columns in ``dataframe_regression``, including when the first value is NA.
+
 2.11.0
 ------
 

src/pytest_regressions/dataframe_regression.py

@@ -260,6 +260,10 @@ def check(
             if isinstance(array.dtype, pd.CategoricalDtype):
                 continue
 
+            # pandas StringDtype columns are supported (#208).
+            if isinstance(array.dtype, pd.StringDtype):
+                continue
+
             # Arrays of strings are supported.
             if (array.dtype.kind == "O") and (type(array.iloc[0]) is str):
                 continue

tests/test_dataframe_regression.py

@@ -305,3 +305,27 @@ def test_categorical(dataframe_regression: DataFrameRegressionFixture) -> None:
 
     df = pd.DataFrame.from_dict({"types": types})
     dataframe_regression.check(df)
+
+
+def test_string_dtype(dataframe_regression: DataFrameRegressionFixture) -> None:
+    """Support for pandas StringDtype columns (#208)."""
+    df = pd.DataFrame(
+        {
+            "name": pd.Series(["Alice", "Bob", "Charlie"], dtype="string"),
+            "age": [25, 30, 35],
+            "city": pd.Series(["New York", "London", "Paris"], dtype="string"),
+        }
+    )
+    dataframe_regression.check(df)
+
+
+def test_string_dtype_with_na(
+    dataframe_regression: DataFrameRegressionFixture,
+) -> None:
+    """StringDtype columns whose first value is NA are still string columns (#208)."""
+    df = pd.DataFrame(
+        {
+            "name": pd.Series([pd.NA, "Bob", "Charlie"], dtype="string"),
+        }
+    )
+    dataframe_regression.check(df)

tests/test_dataframe_regression/test_string_dtype.csv

@@ -0,0 +1,4 @@
+,name,age,city
+0,Alice,25,New York
+1,Bob,30,London
+2,Charlie,35,Paris

tests/test_dataframe_regression/test_string_dtype_with_na.csv

@@ -0,0 +1,4 @@
+,name
+0,
+1,Bob
+2,Charlie