diff --git a/tests/model/mseed_data/test_mseed.py b/tests/model/mseed_data/test_mseed.py
index 2afa9b80c646d2cddd90d93b56ef33c2c9f4325c..e12494dccd68a99c6d69e8a6705c9d561faa3739 100644
--- a/tests/model/mseed_data/test_mseed.py
+++ b/tests/model/mseed_data/test_mseed.py
@@ -229,6 +229,32 @@ class TestMSeed(TestCase):
         self.assertEqual(len(obj.waveform_data['3203']['EL2']['tracesInfo']),
                          1)
 
+    def test_select_2_folders(self):
+        # is_multiplex = True => the selected channel will be read
+        args = {
+            'data_type': 'Q330',
+            'is_multiplex': True,
+            'list_of_dir': [multiplex_data, blockettes_data],
+            'req_soh_chans': [],
+            'req_wf_chans': ['EL2'],
+            'gap_minimum': 60
+        }
+        obj = MSeed(**args)
+        self.assertEqual(list(obj.waveform_data.keys()), ['3203'])
+        self.assertEqual(list(obj.waveform_data['3203'].keys()), ['EL2'])
+        self.assertEqual(obj.waveform_data['3203']['EL2']['samplerate'], 200)
+        self.assertEqual(obj.waveform_data['3203']['EL2']['startTmEpoch'],
+                         1671730004.3100293)
+        self.assertEqual(obj.waveform_data['3203']['EL2']['endTmEpoch'],
+                         1671735657.9148998)
+        self.assertEqual(obj.waveform_data['3203']['EL2']['size'], 268576)
+        self.assertEqual(obj.waveform_data['3203']['EL2']['gaps'],
+                         [[1671730720.5549, 1671735031.2799978]])
+        self.assertEqual(len(obj.waveform_data['3203']['EL2']['tracesInfo']),
+                         1)
+        self.assertEqual(obj.gaps['3203'],
+                         [[1671730720.5549, 1671735031.2799978]])
+
     def test_existing_time_range(self):
         # check if data_time is from the given range, end time may get
         # a little greater than read_end according to record's end time