diff --git a/julearn/pipeline/test/test_merger.py b/julearn/pipeline/tests/test_merger.py
similarity index 92%
rename from julearn/pipeline/test/test_merger.py
rename to julearn/pipeline/tests/test_merger.py
index ebf6b997d..1e151ed34 100644
--- a/julearn/pipeline/test/test_merger.py
+++ b/julearn/pipeline/tests/test_merger.py
@@ -104,3 +104,12 @@ def test_merger_errors() -> None:
         match="must have the same named steps.",
     ):
         merge_pipelines(pipe1, pipe4, search_params=None)
+
+    search_params = {"kind": "grid"}
+    pipe5 = creator2.to_pipeline(search_params={"kind": "bayes"})
+
+    with pytest.raises(
+        ValueError,
+        match="one of the pipelines to merge is a BayesSearchCV",
+    ):
+        merge_pipelines(pipe1, pipe5, search_params=search_params)
\ No newline at end of file
diff --git a/julearn/pipeline/test/test_pipeline_creator.py b/julearn/pipeline/tests/test_pipeline_creator.py
similarity index 100%
rename from julearn/pipeline/test/test_pipeline_creator.py
rename to julearn/pipeline/tests/test_pipeline_creator.py
diff --git a/julearn/pipeline/test/test_target_pipeline.py b/julearn/pipeline/tests/test_target_pipeline.py
similarity index 100%
rename from julearn/pipeline/test/test_target_pipeline.py
rename to julearn/pipeline/tests/test_target_pipeline.py
diff --git a/julearn/pipeline/test/test_target_pipeline_creator.py b/julearn/pipeline/tests/test_target_pipeline_creator.py
similarity index 100%
rename from julearn/pipeline/test/test_target_pipeline_creator.py
rename to julearn/pipeline/tests/test_target_pipeline_creator.py