added tests for ExternalTableDataset

Signed-off-by: Minura Punchihewa <[email protected]>

kedro-datasets/tests/databricks/test_external_table_dataset.py

@@ -0,0 +1,42 @@
+import pytest
+from kedro.io.core import DatasetError
+from pyspark.sql import DataFrame
+
+from kedro_datasets_experimental.databricks.external_table_dataset import ExternalTableDataset
+
+
+class TestExternalTableDataset:
+    def test_location_for_non_existing_table(self):
+        with pytest.raises(DatasetError):
+            ExternalTableDataset(table="test")
+
+    def test_invalid_upsert_write_mode(self):
+        with pytest.raises(DatasetError):
+            ExternalTableDataset(table="test", write_mode="upsert", format="parquet")
+
+    def test_invalid_overwrite_write_mode(self):
+        with pytest.raises(DatasetError):
+            ExternalTableDataset(table="test", write_mode="overwrite", format="parquet")
+
+    def test_save_overwrite_without_location(self):
+        with pytest.raises(DatasetError):
+            ExternalTableDataset(table="test", write_mode="overwrite", format="delta")
+
+    def test_save_overwrite(
+        self,
+        sample_spark_df: DataFrame,
+        append_spark_df: DataFrame,
+        external_location: str,
+    ):
+        unity_ds = ExternalTableDataset(
+            database="test",
+            table="test_save",
+            write_mode="overwrite",
+            location=f"{external_location}/test_save_overwrite_external",
+        )
+        unity_ds.save(sample_spark_df)
+        unity_ds.save(append_spark_df)
+
+        overwritten_table = unity_ds.load()
+
+        assert append_spark_df.exceptAll(overwritten_table).count() == 0