Fix sunz normalization for viirs_compact

[ninahakansson]

SDR data has sun_zenith_angle_correction_applied as default, viirs_compact does not! We now read data with the sunz_corrected modifier and satpy applyes the normalization. Note that reflective bands are
read separately to avoid sunz_correction applied to the IR channels.

• Closes VIIRS compact reflectances not sun normalized #107
• Tests added
• Tests passed: Passes pytest level1c4pps
• Passes flake8

[BengtRydberg]

Why checking just M05? Maybe more clear if you move this check to line 156 and do an assert there (if we do not trust satpy):

assert "sunz_corrected" in scene['M05'].attrs['modifiers']

Or I would recommend that you remove this check and add a new input parameter named sun_zenith_angle_correction_applied to this function so it looks something like this:

def set_header_and_band_attrs(scene, sun_zenith_angle_correction_applied, orbit_n=0):
    if sun_zenith_angle_correction_applied:
        scene[band].attrs['sun_zenith_angle_correction_applied'] = 'True'

Then you can probably remove the comments on line 117 and 118 as well. To me comments is an indication that the code can be written more clear than presently.

and e.g. one line 156 and 159 you can add the following line:

sun_zenith_angle_correction_applied = True

[coveralls]

Pull Request Test Coverage Report for Build 13050156252

Details

• 1 of 6 (16.67%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 78.146%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
level1c4pps/init.py	1	2	50.0%
level1c4pps/viirs2pps_lib.py	0	4	0.0%

Totals
Change from base Build 12688079447:	-0.1%
Covered Lines:	1648
Relevant Lines:	2061

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💛 - Coveralls