Address PR comments - add check that all exposure times are the same value

Author: vmartinez-cu

imap_processing/glows/l2/glows_l2_data.py

@@ -106,7 +106,11 @@ def __post_init__(self, l1b_data: xr.Dataset, position_angle: float) -> None:
         self.photon_flux = np.zeros(self.number_of_bins)
         self.flux_uncertainties = np.zeros(self.number_of_bins)
 
-        if len(self.exposure_times) != 0 and self.exposure_times[0] > 0:
+        if (
+            len(self.exposure_times) != 0
+            and self.exposure_times[0] > 0
+            and len(np.unique(self.exposure_times)) == 1
+        ):
             self.photon_flux = self.raw_histograms / self.exposure_times
             self.flux_uncertainties = raw_uncertainties / self.exposure_times
 

imap_processing/tests/glows/test_glows_l2_data.py

@@ -176,10 +176,9 @@ def test_zero_exposure_bins(l1b_dataset, mock_ecliptic_bin_centers):
 
 
 def test_zero_exposure_values(l1b_dataset, mock_ecliptic_bin_centers):
-    """Zero exposure yields zero flux and zero uncertainty per bin.
+    """Zero exposure yields zero flux and zero uncertainty per bin."""
 
-    Note: all bins have the same exposure time, so if one is zero all are zero.
-    """
+    # Note: all bins have the same exposure time, so if one is zero all are zero.
 
     # Update values used to calculate exposure times to
     # ensure a zero exposure result.
@@ -191,6 +190,7 @@ def test_zero_exposure_values(l1b_dataset, mock_ecliptic_bin_centers):
 
     expected = np.zeros(l1b_dataset.sizes["bins"], dtype=float)
     assert lc.exposure_times.shape == expected.shape
+    assert len(np.unique(lc.exposure_times)) == 1
     assert np.array_equal(lc.exposure_times, expected)
     assert np.array_equal(lc.photon_flux, expected)
     assert np.array_equal(lc.flux_uncertainties, expected)