fix F401

esmtools/tests/test_timeutils.py

@@ -1,63 +1,65 @@
 import pandas as pd
 import pytest
 
-import esmtools
+from esmtools.timeutils import TimeUtilAccessor
 
 
 def test_timeutils_accessor(annual_gregorian):
     """Test that the `timeutils` accessor can be called."""
-    assert annual_gregorian.timeutils._obj.notnull().all()
+    # Calling the TimeUtilAccessor directly in the first instance to not trigger
+    # F401 (importing unused module) from flake8.
+    assert TimeUtilAccessor(annual_gregorian)._obj.notnull().all()
 
 
 def test_annual_factor(
     annual_all_leap, annual_no_leap, annual_gregorian, annual_julian
 ):
     """Tests that the annual factor returned by timeutils is accurate."""
-    assert annual_all_leap["time"].timeutils.annual_factor == 366.0
-    assert annual_no_leap["time"].timeutils.annual_factor == 365.0
-    assert annual_gregorian["time"].timeutils.annual_factor == 365.25
-    assert annual_julian["time"].timeutils.annual_factor == 365.25
+    assert annual_all_leap['time'].timeutils.annual_factor == 366.0
+    assert annual_no_leap['time'].timeutils.annual_factor == 365.0
+    assert annual_gregorian['time'].timeutils.annual_factor == 365.25
+    assert annual_julian['time'].timeutils.annual_factor == 365.25
 
 
 def test_calendar(annual_all_leap, annual_no_leap, annual_gregorian, annual_julian):
     """Tests that the calendar returned by timeutils is accurate."""
-    assert annual_all_leap["time"].timeutils.calendar == "all_leap"
-    assert annual_no_leap["time"].timeutils.calendar == "noleap"
-    assert annual_gregorian["time"].timeutils.calendar == "gregorian"
-    assert annual_julian["time"].timeutils.calendar == "julian"
+    assert annual_all_leap['time'].timeutils.calendar == 'all_leap'
+    assert annual_no_leap['time'].timeutils.calendar == 'noleap'
+    assert annual_gregorian['time'].timeutils.calendar == 'gregorian'
+    assert annual_julian['time'].timeutils.calendar == 'julian'
 
 
-@pytest.mark.parametrize("frequency", ("L", "D", "AS-NOV", "W-TUE"))
+@pytest.mark.parametrize('frequency', ('L', 'D', 'AS-NOV', 'W-TUE'))
 def test_freq(annual_gregorian, frequency):
     """Tests that the calendar frequency returned by timeutils is accurate."""
     data = annual_gregorian
-    data["time"] = pd.date_range("1990", freq=frequency, periods=data.time.size)
-    assert data["time"].timeutils.freq == frequency
+    data['time'] = pd.date_range('1990', freq=frequency, periods=data.time.size)
+    assert data['time'].timeutils.freq == frequency
 
 
 expected_slopes = {
-    "L": 1 / (24 * 60 * 60 * 1e3),
-    "D": 1,
-    "AS-NOV": 365.25,
-    "W-TUE": 7.0,
+    'L': 1 / (24 * 60 * 60 * 1e3),
+    'D': 1,
+    'AS-NOV': 365.25,
+    'W-TUE': 7.0,
 }
 
 
-@pytest.mark.parametrize("frequency", ("L", "D", "AS-NOV", "W-TUE"))
+@pytest.mark.parametrize('frequency', ('L', 'D', 'AS-NOV', 'W-TUE'))
 def test_slope_factor(annual_gregorian, frequency):
     """Tests that the slope factor returned by timeutils is accurate."""
     data = annual_gregorian
-    data["time"] = pd.date_range("1990", freq=frequency, periods=data.time.size)
-    assert data["time"].timeutils.slope_factor == expected_slopes[frequency]
+    data['time'] = pd.date_range('1990', freq=frequency, periods=data.time.size)
+    assert data['time'].timeutils.slope_factor == expected_slopes[frequency]
 
 
 def test_return_numeric_time_datetime(gridded_da_datetime):
     """Tests that datetimes are properly converted to numeric time by timeutils."""
-    data = gridded_da_datetime()["time"]
-    assert data.timeutils.return_numeric_time().dtype == "float64"
+    data = gridded_da_datetime()['time']
+    assert data.timeutils.return_numeric_time().dtype == 'float64'
 
 
 def test_return_numeric_time_cftime(gridded_da_cftime):
     """Tests that cftimes are properly converted to numeric time by timeutils."""
-    data = gridded_da_cftime()["time"]
-    assert data.timeutils.return_numeric_time().dtype == "float64"
+    data = gridded_da_cftime()['time']
+    assert data.timeutils.return_numeric_time().dtype == 'float64'