def test_axis_azimuth():
    apparent_zenith = pd.Series([30])
    apparent_azimuth = pd.Series([90])

    tracker_data = tracking.singleaxis(apparent_zenith, apparent_azimuth,
                                       axis_tilt=0, axis_azimuth=90,
                                       max_angle=90, backtrack=True, 
                                       gcr=2.0/7.0)
    
    expect = pd.DataFrame({'aoi': 30, 'surface_azimuth': 180,
                           'surface_tilt': 0, 'tracker_theta': 0},
                           index=[0], dtype=np.float64)
    
    assert_frame_equal(expect, tracker_data)
    
    apparent_zenith = pd.Series([30])
    apparent_azimuth = pd.Series([180])
    
    tracker_data = tracking.singleaxis(apparent_zenith, apparent_azimuth,
                                       axis_tilt=0, axis_azimuth=90,
                                       max_angle=90, backtrack=True, 
                                       gcr=7.0/2.0)
    
    expect = pd.DataFrame({'aoi': 0, 'surface_azimuth': 180,
                           'surface_tilt': 30, 'tracker_theta': 30},
                           index=[0], dtype=np.float64)
    
    assert_frame_equal(expect, tracker_data)
dataset/ETHPy150Open pvlib/pvlib-python/pvlib/test/test_tracking.py/test_axis_azimuth/swapped operands of `/`