def test_get_single_row_if_channel_missing() -> None:
"""
Test if we can convert a single row of data into a dictionary.
"""
csv_string = StringIO("""id,channel,value
S1,single,foo
""")
df = pd.read_csv(csv_string, sep=",")
row1 = _get_single_channel_row(df, None, "subject")
assert isinstance(row1, dict)
assert row1 == {"channel": "single", "id": "S1", "value": "foo"}
csv_string2 = StringIO("""id,channel,value
S1,double,foo
S1,double,foo
""")
df2 = pd.read_csv(csv_string2, sep=",")
with pytest.raises(ValueError) as ex:
_get_single_channel_row(df2, None, "NoSubject")
assert "NoSubject" in str(ex)
assert "2 rows" in str(ex)
def test_get_single_row() -> None:
"""
Test if we can extract the unique row that has a given value in the "channel" column.
"""
csv_string = StringIO("""id,channel,value
S1,single,foo
S2,double,bar
S2,double,baz
""")
df = pd.read_csv(csv_string, sep=",")
row1 = _get_single_channel_row(df, "single", "subject")
assert isinstance(row1, dict)
# The returned dictionary appears to have its columns sorted by name, not in the order in the datafile!
assert row1 == {"channel": "single", "id": "S1", "value": "foo"}
with pytest.raises(ValueError) as ex:
_get_single_channel_row(df, "notPresent", "NoSubject")
assert "NoSubject" in str(ex)
assert "0 rows" in str(ex)
with pytest.raises(ValueError) as ex:
_get_single_channel_row(df, "double", "NoSubject")
assert "NoSubject" in str(ex)
assert "2 rows" in str(ex)