JP-3616: Fix NIRSpec FS spec3 slit name (#8470)

CHANGES.rst

@@ -57,11 +57,15 @@ extract_1d
   regions are specified and the lower and upper limits for one of them are
   outside the valid area for some data range. [#8433]
 
+- Correct the output slit name for non-primary slit extractions in the
+  spec3 pipeline, for NIRSpec fixed slit mode. [#8470]
+
 extract_2d
 ----------
 
 - Added handling for NIRCam GRISM time series pointing offsets. [#8449]
 
+
 flat_field
 ----------
 

jwst/extract_1d/extract.py

@@ -2986,7 +2986,10 @@ def do_extract1d(
 
             # For NRS_FIXEDSLIT, the slit name comes from the FXD_SLIT keyword in the model meta
             if input_model.meta.exposure.type == 'NRS_FIXEDSLIT':
-                slitname = input_model.meta.instrument.fixed_slit
+                if hasattr(input_model, "name") and input_model.name is not None:
+                    slitname = input_model.name
+                else:
+                    slitname = input_model.meta.instrument.fixed_slit
 
             # Loop over all spectral orders available for extraction
             prev_offset = OFFSET_NOT_ASSIGNED_YET

jwst/extract_1d/tests/test_extract_1d_step.py

@@ -0,0 +1,118 @@
+import numpy as np
+import pytest
+import stdatamodels.jwst.datamodels as dm
+
+from jwst.assign_wcs.util import wcs_bbox_from_shape
+from jwst.extract_1d.extract_1d_step import Extract1dStep
+
+
+@pytest.fixture
+def simple_wcs():
+    shape = (50, 50)
+    xcenter = shape[1] // 2.0
+
+    def simple_wcs_function(x, y):
+        """ Simple WCS for testing """
+        crpix1 = xcenter
+        crpix3 = 1.0
+        cdelt1 = 0.1
+        cdelt2 = 0.1
+        cdelt3 = 0.01
+
+        crval1 = 45.0
+        crval2 = 45.0
+        crval3 = 7.5
+
+        wave = (x + 1 - crpix3) * cdelt3 + crval3
+        ra = (x + 1 - crpix1) * cdelt1 + crval1
+        dec = np.full_like(ra, crval2 + 1 * cdelt2)
+
+        return ra, dec, wave
+
+    simple_wcs_function.bounding_box = wcs_bbox_from_shape(shape)
+
+    return simple_wcs_function
+
+
+@pytest.fixture()
+def mock_nirspec_fs_one_slit(simple_wcs):
+    model = dm.SlitModel()
+    model.meta.instrument.name = 'NIRSPEC'
+    model.meta.instrument.detector = 'NRS1'
+    model.meta.observation.date = '2023-07-22'
+    model.meta.observation.time = '06:24:45.569'
+    model.meta.instrument.fixed_slit = 'S200A1'
+    model.meta.exposure.type = 'NRS_FIXEDSLIT'
+    model.meta.subarray.name = 'ALLSLITS'
+
+    model.source_type = 'EXTENDED'
+    model.meta.wcsinfo.dispersion_direction = 1
+    model.meta.wcs = simple_wcs
+
+    model.data = np.arange(50 * 50, dtype=float).reshape((50, 50))
+    model.var_poisson = model.data * 0.02
+    model.var_rnoise = model.data * 0.02
+    model.var_flat = model.data * 0.05
+    yield model
+    model.close()
+
+
+@pytest.fixture()
+def mock_nirspec_mos(mock_nirspec_fs_one_slit):
+    model = dm.MultiSlitModel()
+    model.meta.instrument.name = 'NIRSPEC'
+    model.meta.instrument.detector = 'NRS1'
+    model.meta.observation.date = '2023-07-22'
+    model.meta.observation.time = '06:24:45.569'
+    model.meta.exposure.type = 'NRS_MSASPEC'
+
+    nslit = 3
+    for i in range(nslit):
+        slit = mock_nirspec_fs_one_slit.copy()
+        slit.name = str(i + 1)
+        model.slits.append(slit)
+
+    yield model
+    model.close()
+
+
+@pytest.mark.parametrize('slit_name', [None, 'S200A1', 'S1600A1'])
+def test_extract_nirspec_fs_slit(mock_nirspec_fs_one_slit, simple_wcs, slit_name):
+    mock_nirspec_fs_one_slit.name = slit_name
+    result = Extract1dStep.call(mock_nirspec_fs_one_slit)
+    assert result.meta.cal_step.extract_1d == 'COMPLETE'
+
+    if slit_name is None:
+        assert (result.spec[0].name
+                == mock_nirspec_fs_one_slit.meta.instrument.fixed_slit)
+    else:
+        assert result.spec[0].name == slit_name
+
+    # output wavelength is the same as input
+    _, _, expected_wave = simple_wcs(np.arange(50), np.arange(50))
+    assert np.allclose(result.spec[0].spec_table['WAVELENGTH'], expected_wave)
+
+    # output flux and errors are non-zero, exact values will depend
+    # on extraction parameters
+    assert np.all(result.spec[0].spec_table['FLUX'] > 0)
+    assert np.all(result.spec[0].spec_table['FLUX_ERROR'] > 0)
+    result.close()
+
+
+def test_extract_nirspec_mos_multi_slit(mock_nirspec_mos, simple_wcs):
+    result = Extract1dStep.call(mock_nirspec_mos)
+    assert result.meta.cal_step.extract_1d == 'COMPLETE'
+
+    for i, spec in enumerate(result.spec):
+        assert spec.name == str(i + 1)
+
+        # output wavelength is the same as input
+        _, _, expected_wave = simple_wcs(np.arange(50), np.arange(50))
+        assert np.allclose(spec.spec_table['WAVELENGTH'], expected_wave)
+
+        # output flux and errors are non-zero, exact values will depend
+        # on extraction parameters
+        assert np.all(spec.spec_table['FLUX'] > 0)
+        assert np.all(spec.spec_table['FLUX_ERROR'] > 0)
+
+    result.close()