Updated to fallback to RA, DEC header keywords for unusable WCS (#78)

* Updated to fallback to RA, DEC header keywords for unusable WCS coordinate values

* Updated docstring in test_gnirs.ad fixture

* Created test to check bug behavior

* Added test using monkeypatch to simulate the wcs coordinate failures

* Added test using monkeypatch to simulate the wcs coordinate failures

Co-authored-by: Oliver <oly@oberdorf.org>
Co-authored-by: Bruno Quint <b1quint@gmail.com>

gemini_instruments/gnirs/adclass.py

@@ -431,6 +431,8 @@ def ra(self):
         # if it's messed up
 
         wcs_ra = self.wcs_ra()
+        if wcs_ra is None:
+            return self.phu.get('RA', None)
         try:
             tgt_ra = self.target_ra(offset=True, icrs=True)
         except:  # Return WCS value if we can't get our sanity check
@@ -469,6 +471,8 @@ def dec(self):
         # if it's messed up
 
         wcs_dec = self.wcs_dec()
+        if wcs_dec is None:
+            return self.phu.get('DEC', None)
         try:
             tgt_dec = self.target_dec(offset=True, icrs=True)
         except:  # Return WCS value if we can't get our sanity check

gemini_instruments/gnirs/tests/test_gnirs.py

@@ -22,6 +22,20 @@
 
 @pytest.fixture(params=test_files)
 def ad(request):
+    """
+    Fixture that will download a file from specified as a test parameter,
+    open it as an AstroData object and return it.
+
+    Parameters
+    ----------
+    request : fixture
+        Pytest built-in fixture containing information about the parent test.
+
+    Returns
+    -------
+    AstroData
+        Raw file downloaded from the archive and cached locally.
+    """
     filename = request.param
     path = astrodata.testing.download_from_archive(filename)
     return astrodata.open(path)
@@ -103,3 +117,45 @@ def test_descriptor_matches_type(ad, descriptor, expected_type):
     value = getattr(ad, descriptor)()
     assert isinstance(value, expected_type) or value is None, \
         "Assertion failed for file: {}".format(ad.filename)
+
+
+@pytest.mark.dragons_remote_data
+@pytest.mark.parametrize("ad", ["N20190101S0102.fits"], indirect=True)
+def test_ra_and_dec_always_returns_float(ad, monkeypatch):
+    """
+    Tests that the get the RA/DEC coordinates using descriptors.
+
+    Parameters
+    ----------
+    ad : fixture
+        Custom fixture that downloads and opens the input file.
+    """
+    if isinstance(ad.wcs_ra(), float) or ad.wcs_ra() is None:
+        assert isinstance(ad.ra(), float)
+
+    if isinstance(ad.wcs_dec(), float) or ad.wcs_dec() is None:
+        assert isinstance(ad.dec(), float)
+
+
+@pytest.mark.dragons_remote_data
+@pytest.mark.parametrize("ad", ["N20190101S0102.fits"], indirect=True)
+def test_ra_and_dec_wcs_fallback(ad, monkeypatch):
+    """
+    Tests that the get the RA/DEC coordinates using descriptors when the WCS coordinate mapping fails
+
+    Parameters
+    ----------
+    ad : fixture
+        Custom fixture that downloads and opens the input file.
+    """
+    def _fake_wcs_call():
+        return None
+
+    monkeypatch.setattr(ad, 'wcs_ra', _fake_wcs_call)
+    monkeypatch.setattr(ad, 'wcs_dec', _fake_wcs_call)
+    assert(ad.ra() == ad.phu.get('RA', None))
+    assert(ad.dec() == ad.phu.get('DEC', None))
+
+
+if __name__ == "__main__":
+    pytest.main()