Rename Fits class in units.format to FITS

astropy/units/format/__init__.py

@@ -4,17 +4,20 @@
 A collection of different unit formats.
 """
 
+import sys
+import warnings
+
+from astropy.utils.exceptions import AstropyDeprecationWarning
+
 # This is pretty atrocious, but it will prevent a circular import for those
 # formatters that need access to the units.core module An entry for it should
 # exist in sys.modules since astropy.units.core imports this module
-import sys
-
 core = sys.modules["astropy.units.core"]
 
 from .base import Base
 from .cds import CDS
 from .console import Console
-from .fits import Fits
+from .fits import FITS
 from .generic import Generic, Unscaled
 from .latex import Latex, LatexInline
 from .ogip import OGIP
@@ -26,7 +29,7 @@
     "Generic",
     "CDS",
     "Console",
-    "Fits",
+    "FITS",
     "Latex",
     "LatexInline",
     "OGIP",
@@ -37,6 +40,19 @@
 ]
 
 
+def __getattr__(name):
+    if name == "Fits":
+        warnings.warn(
+            AstropyDeprecationWarning(
+                'The class "Fits" has been renamed to "FITS" in version 7.0. The old '
+                "name is deprecated and may be removed in a future version.\n"
+                "        Use FITS instead."
+            )
+        )
+        return FITS
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+
 def _known_formats():
     inout = [
         name

astropy/units/format/fits.py

@@ -12,7 +12,7 @@
 from . import core, generic, utils
 
 
-class Fits(generic.Generic):
+class FITS(generic.Generic):
     """
     The FITS standard unit format.
 

astropy/units/tests/test_format.py

@@ -16,6 +16,7 @@
 from astropy.units import PrefixUnit, Unit, UnitBase, UnitsWarning, dex
 from astropy.units import format as u_format
 from astropy.units.utils import is_effectively_unity
+from astropy.utils.exceptions import AstropyDeprecationWarning
 
 
 @pytest.mark.parametrize(
@@ -306,13 +307,13 @@ def test_roundtrip(self, unit):
 
 class TestRoundtripFITS(RoundtripBase):
     format_ = "fits"
-    deprecated_units = u_format.Fits._deprecated_units
+    deprecated_units = u_format.FITS._deprecated_units
 
     @pytest.mark.parametrize(
         "unit",
         [
             unit
-            for unit in u_format.Fits._units.values()
+            for unit in u_format.FITS._units.values()
             if (isinstance(unit, UnitBase) and not isinstance(unit, PrefixUnit))
         ],
     )
@@ -388,7 +389,7 @@ def test_roundtrip(self, unit):
 
 
 def test_fits_units_available():
-    u_format.Fits._units
+    u_format.FITS._units
 
 
 def test_vo_units_available():
@@ -566,7 +567,7 @@ def test_fits_to_string_function_error():
     """
 
     with pytest.raises(TypeError, match="unit argument must be"):
-        u_format.Fits.to_string(None)
+        u_format.FITS.to_string(None)
 
 
 def test_fraction_repr():
@@ -650,7 +651,7 @@ def test_fits_function(string):
     # Function units cannot be written, so ensure they're not parsed either.
     with pytest.raises(ValueError):
         print(string)
-        u_format.Fits().parse(string)
+        u_format.FITS().parse(string)
 
 
 @pytest.mark.parametrize("string", ["mag(ct/s)", "dB(mW)", "dex(cm s**-2)"])
@@ -1003,3 +1004,16 @@ def test_format_latex_one(format_spec, expected_mantissa):
     m, ex = split_mantissa_exponent(1, format_spec)
     assert ex == ""
     assert m == expected_mantissa
+
+
+def test_Fits_name_deprecation():
+    with pytest.warns(
+        AstropyDeprecationWarning,
+        match=(
+            r'^The class "Fits" has been renamed to "FITS" in version 7\.0\. '
+            r"The old name is deprecated and may be removed in a future version\.\n"
+            r"        Use FITS instead\.$"
+        ),
+    ):
+        from astropy.units.format import Fits
+    assert Fits is u.format.FITS

docs/changes/units/16455.api.rst

@@ -0,0 +1,4 @@
+The ``format.Fits`` formatter class has been renamed to ``format.FITS`` and the
+old name is deprecated.
+Specifying the FITS format for converting ``Quantity`` and ``UnitBase``
+instances to and from strings is not affected by this change.