Merge pull request #37 from DeaMariaLeon/test

Test: Trying to use hypothesis for Expr.is_null()

requirements-dev.txt

@@ -5,3 +5,4 @@ pre-commit
 pyarrow
 pytest
 pytest-cov
+hypothesis

tests/hypothesis/test_basic_arithmetic.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import pandas as pd
+import polars as pl
+from hypothesis import given
+from hypothesis import strategies as st
+from numpy.testing import assert_allclose
+
+import narwhals as nw
+
+
+@given(
+    st.lists(
+        st.integers(min_value=-9223372036854775807, max_value=9223372036854775807),
+        min_size=3,
+        max_size=3,
+    ),
+    st.lists(
+        st.floats(min_value=-9223372036854775807.0, max_value=9223372036854775807.0),
+        min_size=3,
+        max_size=3,
+    ),
+)  # type: ignore[misc]
+def test_mean(
+    integer: st.SearchStrategy[list[int]],
+    floats: st.SearchStrategy[float],
+) -> None:
+    df_pandas = pd.DataFrame(
+        {
+            "integer": integer,
+            "floats": floats,
+        }
+    )
+    df_polars = pl.DataFrame(
+        {
+            "integer": integer,
+            "floats": floats,
+        },
+    )
+    df_nw1 = nw.DataFrame(df_pandas)
+    df_nw2 = nw.DataFrame(df_polars)
+
+    assert_allclose(
+        nw.to_native(df_nw1.select(nw.col("integer").mean())),
+        nw.to_native(df_nw2.select(nw.col("integer").mean())),
+    )
+    assert_allclose(
+        nw.to_native(df_nw1.select(nw.col("floats").mean())),
+        nw.to_native(df_nw2.select(nw.col("floats").mean())),
+    )