rcal-952 Update grism flat field tests with correct input (#1531)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

romancal/regtest/test_wfi_flat_field.py

@@ -34,14 +34,14 @@ def test_flat_field_image_step(rtdata, ignore_asdf_paths):
     assert diff.identical, diff.report()
 
 
-@pytest.mark.xfail(reason="Wrong input for the purpose of this test")
+# @pytest.mark.xfail(reason="Wrong input for the purpose of this test")
 @pytest.mark.bigdata
 def test_flat_field_grism_step(rtdata, ignore_asdf_paths):
     """Test for the flat field step using grism data. The reference file for
     the grism and prism data should be None, only testing the grism
     case here."""
 
-    input_file = "r0000201001001001001_0001_wfi01_uncal.asdf"
+    input_file = "r0000201001001001001_0001_wfi01_assignwcs.asdf"
     rtdata.get_data(f"WFI/grism/{input_file}")
     rtdata.input = input_file
 
@@ -64,6 +64,8 @@ def test_flat_field_grism_step(rtdata, ignore_asdf_paths):
     rtdata.output = output
     args = ["romancal.step.FlatFieldStep", rtdata.input]
     RomanStep.from_cmdline(args)
+    output_model = rdm.open(rtdata.output)
+    assert output_model.meta.cal_step.flat_field == "SKIPPED"
     rtdata.get_truth(f"truth/WFI/grism/{output}")
     diff = compare_asdf(rtdata.output, rtdata.truth, **ignore_asdf_paths)
     assert diff.identical, diff.report()