diff --git a/tests/_expected.py b/tests/_expected.py
index a27b2f5..817b4a6 100644
--- a/tests/_expected.py
+++ b/tests/_expected.py
@@ -2,6 +2,7 @@
 from pathlib import Path
 
 import pandas as pd
+import polars as pl
 
 TEST_DIR = Path(__file__).parent
 DATA_DIR = TEST_DIR / "data"
@@ -28,15 +29,18 @@
         "+--------+-----------+---------+--------+-----------+---------+",
 """
 
-DF_OVERLAP = (mdpd.from_md(EXPECTED_OVERLAP)
-              .astype({'pos_start_1': 'int64'})
-              .astype({'pos_end_1': 'int64'})
-              .astype({'pos_start_2': 'int64'})
-              .astype({'pos_end_2': 'int64'}))
+# Pandas
+PD_DF_OVERLAP = (mdpd.from_md(EXPECTED_OVERLAP)
+                 .astype({'pos_start_1': 'int64'})
+                 .astype({'pos_end_1': 'int64'})
+                 .astype({'pos_start_2': 'int64'})
+                 .astype({'pos_end_2': 'int64'}))
 
-DF_OVERLAP = DF_OVERLAP.sort_values(by=list(DF_OVERLAP.columns)).reset_index(drop=True)
+PD_DF_OVERLAP = PD_DF_OVERLAP.sort_values(by=list(PD_DF_OVERLAP.columns)).reset_index(drop=True)
+PD_DF1 = pd.read_csv(f"{DATA_DIR}/reads.csv")
+PD_DF2 = pd.read_csv(f"{DATA_DIR}/targets.csv")
 
-
-
-DF1 = pd.read_csv(f"{DATA_DIR}/reads.csv")
-DF2 = pd.read_csv(f"{DATA_DIR}/targets.csv")
\ No newline at end of file
+# Polars
+PL_DF_OVERLAP = pl.DataFrame(PD_DF_OVERLAP)
+PL_DF1 = pl.DataFrame(PD_DF1)
+PL_DF2 = pl.DataFrame(PD_DF2)
\ No newline at end of file
diff --git a/tests/test_pandas_overlap.py b/tests/test_pandas_overlap.py
index 36dd0cd..5b792e0 100644
--- a/tests/test_pandas_overlap.py
+++ b/tests/test_pandas_overlap.py
@@ -1,21 +1,17 @@
 import pandas as pd
 
 import polars_bio as pb
-from _expected import DF_OVERLAP, DF1, DF2
-
-
-
-
+from _expected import PD_DF_OVERLAP, PD_DF1, PD_DF2
 
 
 class TestOverlapPandas:
+    result = pb.overlap(PD_DF1, PD_DF2, output_type="pandas.DataFrame")
     def test_overlap_count(self):
-        assert len(pb.overlap(DF1, DF2, output_type="pandas.DataFrame")) == 16
+        assert len(self.result) == 16
 
     def test_overlap_schema_rows(self):
-        result = pb.overlap(DF1, DF2, output_type="pandas.DataFrame")
-        result = result.sort_values(by=list(result.columns)).reset_index(drop=True)
-        expected = DF_OVERLAP
+        result = self.result.sort_values(by=list(self.result.columns)).reset_index(drop=True)
+        expected = PD_DF_OVERLAP
         pd.testing.assert_frame_equal(result, expected)
 
 
diff --git a/tests/test_polars_overlap.py b/tests/test_polars_overlap.py
index 8eb92c3..6e3701f 100644
--- a/tests/test_polars_overlap.py
+++ b/tests/test_polars_overlap.py
@@ -1,4 +1,22 @@
 import pandas as pd
-import polars_bio.overlap as overlap
+import polars_bio as pb
+from _expected import PL_DF_OVERLAP, PL_DF1, PL_DF2
 
 
+class TestOverlapPolars:
+
+    result_frame = pb.overlap(PL_DF1, PL_DF2, output_type="polars.DataFrame")
+    result_lazy = pb.overlap(PL_DF1, PL_DF2, output_type="polars.LazyFrame").collect()
+    expected = PL_DF_OVERLAP
+
+    def test_overlap_count(self):
+        assert len(self.result_frame) == 16
+        assert len(self.result_lazy) == 16
+
+    def test_overlap_schema_rows(self):
+        result = self.result_frame.sort(by=self.result_frame.columns)
+        assert self.expected.equals(result)
+
+    def test_overlap_schema_rows_lazy(self):
+        result = self.result_lazy.sort(by=self.result_lazy.columns)
+        assert self.expected.equals(result)