Fix unit tests

Author: myd7349

mne/io/nihon/nihon.py

@@ -280,7 +280,7 @@ def _read_nihon_header(fname):
                     "Cannot read NK file with different sfreq in each datablock"
                 )
 
-    return header
+    return header, _chan_labels
 
 
 def _read_event_log_block(fid, t_block, version):
@@ -380,13 +380,13 @@ def _map_ch_to_type(ch_name):
     return "eeg"
 
 
-def _map_ch_to_specs(ch_name, ch_names_upper):
+def _map_ch_to_specs(ch_name, chan_labels_upper):
     unit_mult = 1e-3
     phys_min = -12002.9
     phys_max = 12002.56
     dig_min = -32768
-    if ch_name.upper() in ch_names_upper:
-        idx = ch_names_upper.index(ch_name.upper())
+    if ch_name.upper() in chan_labels_upper:
+        idx = chan_labels_upper.index(ch_name.upper())
         if (idx < 42 or idx > 73) and idx not in [76, 77]:
             unit_mult = 1e-6
             phys_min = -3200
@@ -432,7 +432,9 @@ def __init__(self, fname, preload=False, *, encoding="utf-8", verbose=None):
         data_name = fname.name
         logger.info(f"Loading {data_name}")
 
-        header = _read_nihon_header(fname)
+        # chan_labels contains the electrode codes defined
+        # in the .21E file. It is not the same as header["ch_names"].
+        header, chan_labels = _read_nihon_header(fname)
         metadata = _read_nihon_metadata(fname)
 
         # n_chan = len(header['ch_names']) + 1
@@ -448,8 +450,8 @@ def __init__(self, fname, preload=False, *, encoding="utf-8", verbose=None):
             with info._unlock():
                 info["meas_date"] = metadata["meas_date"]
 
-        ch_names_upper = [x.upper() for x in info["ch_names"]]
-        chs = {x: _map_ch_to_specs(x, ch_names_upper) for x in info["ch_names"]}
+        chan_labels_upper = [x.upper() for x in chan_labels]
+        chs = {x: _map_ch_to_specs(x, chan_labels_upper) for x in info["ch_names"]}
         cal = np.array([chs[x]["cal"] for x in info["ch_names"]], float)[:, np.newaxis]
         offsets = np.array([chs[x]["offset"] for x in info["ch_names"]], float)[
             :, np.newaxis

mne/io/nihon/tests/test_nihon.py

@@ -48,7 +48,7 @@ def test_nihon_eeg():
         raw = read_raw_nihon(fname_edf, preload=True)
 
     with pytest.raises(ValueError, match="Not a valid Nihon Kohden EEG file"):
-        raw = _read_nihon_header(fname_edf)
+        header, _ = _read_nihon_header(fname_edf)
 
     bad_fname = data_path / "eximia" / "text_eximia.nxe"