diff --git a/tests/gentropy/dataset/test_study_locus.py b/tests/gentropy/dataset/test_study_locus.py
index f4f80fbda..0ae7ef2d5 100644
--- a/tests/gentropy/dataset/test_study_locus.py
+++ b/tests/gentropy/dataset/test_study_locus.py
@@ -764,7 +764,7 @@ def _setup(self: TestStudyLocusWindowClumping, spark: SparkSession) -> None:
                 ).withColumns(
                     {
                         "studyLocusId": f.monotonically_increasing_id().cast(
-                            t.LongType()
+                            t.StringType()
                         ),
                         "pValueMantissa": f.lit(1).cast(t.FloatType()),
                         "variantId": f.concat(