Create test_helpers.py

tests/test_helpers.py

@@ -0,0 +1,35 @@
+from pathlib import Path
+
+import pandas as pd
+
+from examples.helpers import with_parquet_cache
+
+
+class TestWithParquetCache:
+    def test_creates_and_fetches_cache(self, tmp_path: Path):
+        fp = tmp_path / "test.parquet"
+        sample_df = pd.DataFrame({"a": [1, 2, 3]})
+
+        @with_parquet_cache(fp=tmp_path / "test.parquet")
+        def myfunc() -> pd.DataFrame:
+            return sample_df
+
+        assert not fp.exists()
+        _df = myfunc()
+        pd.testing.assert_frame_equal(_df, sample_df)
+        assert fp.exists()
+
+        df2 = myfunc()
+        pd.testing.assert_frame_equal(df2, sample_df)
+
+    def test_doesnt_run_the_func_if_file_exists(self, tmp_path: Path):
+        fp = tmp_path / "test.parquet"
+        sample_df = pd.DataFrame({"a": [1, 2, 3]})
+        sample_df.to_parquet(fp)
+
+        @with_parquet_cache(fp=tmp_path / "test.parquet")
+        def myfunc() -> pd.DataFrame:
+            return 1 / 0
+
+        _df = myfunc()
+        pd.testing.assert_frame_equal(_df, sample_df)