diff --git a/tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb b/tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb
old mode 100755
new mode 100644
index 563055c3..dc00cbd3
Binary files a/tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb and b/tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb differ
diff --git a/tests/test_nwb_utils.py b/tests/test_nwb_utils.py
index a20d6677..3c59d189 100644
--- a/tests/test_nwb_utils.py
+++ b/tests/test_nwb_utils.py
@@ -1,6 +1,17 @@
-from ipfx.dataset.create import is_file_mies
+from ipfx.dataset.create import is_file_mies, create_ephys_data_set
 
-TEST_NWB_FILE_PATH = 'tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb'
+TEST_MIES_FILE_PATH = 'tests/data/nwb/Ctgf-T2A-dgCre;Ai14-495723.05.02.01.nwb'
+TEST_NON_MIES_FILE_PATH = 'tests/data/2018_03_20_0005.nwb'
 
 def test_is_file_mies():
-    assert is_file_mies(TEST_NWB_FILE_PATH) == True
\ No newline at end of file
+    assert is_file_mies(TEST_MIES_FILE_PATH) == True
+
+def test_is_file_mies_with_non_mies_file():
+    """
+    Tests the case where the file is not detected as a MIES file.
+    The file is read using the ipfx.dataset.hbg_nwb_data.HBGNWBData class.
+    """
+    assert is_file_mies(TEST_NON_MIES_FILE_PATH) == False
+    nwb_data = create_ephys_data_set(TEST_NON_MIES_FILE_PATH)
+    assert nwb_data is not None
+    assert len(nwb_data.ontology.stimuli) > 0
\ No newline at end of file