mhvk · Dec 5, 2016 · Dec 5, 2016
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -404,6 +404,11 @@ Other Changes and Additions
   that require only data from data.astropy.org, and ``--remote-data=any`` is
   the same as ``--remote-data`` (run all tests that use remote data). [#5506]
 
+- The pytest ``recwarn`` fixture has been removed from the tests in favor of
+  ``utils.catch_warnings``. [#5489]
+
+- Deprecated escape sequences in strings (Python 3.6) have been removed. [#5489]
+
 1.2.2 (unreleased)
 ------------------
 

diff --git a/astropy/_erfa/erfa_generator.py b/astropy/_erfa/erfa_generator.py
@@ -300,15 +300,15 @@ def __init__(self, name, source_path, match_line=None):
             else:
                 filecontents = f.read()
 
-        pattern = "\n([^\n]+{0} ?\([^)]+\)).+?(/\*.+?\*/)".format(name)
+        pattern = r"\n([^\n]+{0} ?\([^)]+\)).+?(/\*.+?\*/)".format(name)
         p = re.compile(pattern, flags=re.DOTALL|re.MULTILINE)
 
         search = p.search(filecontents)
         self.cfunc = " ".join(search.group(1).split())
         self.doc = FunctionDoc(search.group(2))
 
         self.args = []
-        for arg in re.search("\(([^)]+)\)", self.cfunc).group(1).split(', '):
+        for arg in re.search(r"\(([^)]+)\)", self.cfunc).group(1).split(', '):
             self.args.append(Argument(arg, self.doc))
         self.ret = re.search("^(.*){0}".format(name), self.cfunc).group(1).strip()
         if self.ret != 'void':
@@ -391,14 +391,14 @@ def surround(a_list, pre, post):
         erfa_h = f.read()
 
     funcs = OrderedDict()
-    section_subsection_functions = re.findall('/\* (\w*)/(\w*) \*/\n(.*?)\n\n',
+    section_subsection_functions = re.findall(r'/\* (\w*)/(\w*) \*/\n(.*?)\n\n',
                                               erfa_h, flags=re.DOTALL|re.MULTILINE)
     for section, subsection, functions in section_subsection_functions:
         print_("{0}.{1}".format(section, subsection))
         if ((section == "Astronomy") or (subsection == "AngleOps")
             or (subsection == "SphericalCartesian")
             or (subsection == "MatrixVectorProducts")):
-            func_names = re.findall(' (\w+)\(.*?\);', functions, flags=re.DOTALL)
+            func_names = re.findall(r' (\w+)\(.*?\);', functions, flags=re.DOTALL)
             for name in func_names:
                 print_("{0}.{1}.{2}...".format(section, subsection, name))
                 if multifilserc:
@@ -409,7 +409,7 @@ def surround(a_list, pre, post):
                     # the start of the header declaration, otherwise it
                     # might find a *call* of the function instead of the
                     # definition
-                    for line in functions.split('\n'):
+                    for line in functions.split(r'\n'):
                         if name in line:
                             # [:-1] is to remove trailing semicolon, and
                             # splitting on '(' is because the header and
@@ -433,9 +433,9 @@ def surround(a_list, pre, post):
         erfa_m_h = f.read()
     constants = []
     for chunk in erfa_m_h.split("\n\n"):
-        result = re.findall("#define (ERFA_\w+?) (.+?)$", chunk, flags=re.DOTALL|re.MULTILINE)
+        result = re.findall(r"#define (ERFA_\w+?) (.+?)$", chunk, flags=re.DOTALL|re.MULTILINE)
         if result:
-            doc = re.findall("/\* (.+?) \*/\n", chunk, flags=re.DOTALL)
+            doc = re.findall(r"/\* (.+?) \*/\n", chunk, flags=re.DOTALL)
             for (name, value) in result:
                 constants.append(Constant(name, value, doc))
 

diff --git a/astropy/_erfa/tests/test_erfa.py b/astropy/_erfa/tests/test_erfa.py
@@ -2,6 +2,7 @@
 
 import numpy as np
 from .. import core as erfa
+from ...tests.helper import catch_warnings
 
 
 def test_erfa_wrapper():
@@ -93,7 +94,7 @@ def test_spherical_cartesian():
     np.testing.assert_allclose(pv, [[0.0,np.sqrt(2.0),np.sqrt(2.0)],[-1.0,0.0,0.0]], atol=1e-14)
 
 
-def test_errwarn_reporting(recwarn):
+def test_errwarn_reporting():
     """
     Test that the ERFA error reporting mechanism works as it should
     """
@@ -102,14 +103,18 @@ def test_errwarn_reporting(recwarn):
     erfa.dat(1990, 1, 1, 0.5)
 
     # check warning is raised for a scalar
-    erfa.dat(100, 1, 1, 0.5)
-    w = recwarn.pop(erfa.ErfaWarning)
-    assert '1 of "dubious year (Note 1)"' in str(w.message)
+    with catch_warnings() as w:
+        erfa.dat(100, 1, 1, 0.5)
+        assert len(w) == 1
+        assert w[0].category == erfa.ErfaWarning
+        assert '1 of "dubious year (Note 1)"' in str(w[0].message)
 
     # and that the count is right for a vector.
-    erfa.dat([100, 200, 1990], 1, 1, 0.5)
-    w = recwarn.pop(erfa.ErfaWarning)
-    assert '2 of "dubious year (Note 1)"' in str(w.message)
+    with catch_warnings() as w:
+        erfa.dat([100, 200, 1990], 1, 1, 0.5)
+        assert len(w) == 1
+        assert w[0].category == erfa.ErfaWarning
+        assert '2 of "dubious year (Note 1)"' in str(w[0].message)
 
     try:
         erfa.dat(1990, [1, 34, 2], [1, 1, 43], 0.5)

diff --git a/astropy/coordinates/sky_coordinate.py b/astropy/coordinates/sky_coordinate.py
@@ -1169,7 +1169,7 @@ def from_pixel(cls, xp, yp, wcs, origin=0, mode='all'):
     # Table interactions
     @classmethod
     def guess_from_table(cls, table, **coord_kwargs):
-        """
+        r"""
         A convenience method to create and return a new `SkyCoord` from the data
         in an astropy Table.
 

diff --git a/astropy/coordinates/tests/test_angles.py b/astropy/coordinates/tests/test_angles.py
@@ -856,7 +856,7 @@ def test_repr_latex():
     arrangle = Angle([1, 2.1], u.deg)
     rlarrangle = arrangle._repr_latex_()
 
-    assert rlscangle == '$2^\circ06{}^\prime00{}^{\prime\prime}$'
+    assert rlscangle == r'$2^\circ06{}^\prime00{}^{\prime\prime}$'
     assert rlscangle.split('$')[1] in rlarrangle
 
     # make sure the ... appears for large arrays

diff --git a/astropy/coordinates/tests/test_iau_fullstack.py b/astropy/coordinates/tests/test_iau_fullstack.py
@@ -13,7 +13,7 @@
 from ..builtin_frames.utils import get_jd12
 from .. import EarthLocation
 from .. import SkyCoord
-from ...tests.helper import pytest
+from ...tests.helper import pytest, catch_warnings
 from ... import _erfa as erfa
 from ...utils import iers
 from .utils import randomly_sample_sphere
@@ -138,7 +138,7 @@ def test_fiducial_roudtrip(fullstack_icrs, fullstack_fiducial_altaz):
     npt.assert_allclose(fullstack_icrs.dec.deg, icrs2.dec.deg)
 
 
-def test_future_altaz(recwarn):
+def test_future_altaz():
     """
     While this does test the full stack, it is mostly meant to check that a
     warning is raised when attempting to get to AltAz in the future (beyond
@@ -152,10 +152,12 @@ def test_future_altaz(recwarn):
     if hasattr(utils, '__warningregistry__'):
         utils.__warningregistry__.clear()
 
-    location = EarthLocation(lat=0*u.deg, lon=0*u.deg)
-    t = Time('J2161')
+    with catch_warnings() as found_warnings:
 
-    SkyCoord(1*u.deg, 2*u.deg).transform_to(AltAz(location=location, obstime=t))
+        location = EarthLocation(lat=0*u.deg, lon=0*u.deg)
+        t = Time('J2161')
+
+        SkyCoord(1*u.deg, 2*u.deg).transform_to(AltAz(location=location, obstime=t))
 
     # check that these message(s) appear among any other warnings.  If tests are run with
     # --remote-data then the IERS table will be an instance of IERS_Auto which is
@@ -167,7 +169,7 @@ def test_future_altaz(recwarn):
         messages_to_find.append("(some) times are outside of range covered by IERS table.")
 
     messages_found = [False for _ in messages_to_find]
-    for w in recwarn.list:
+    for w in found_warnings:
         if issubclass(w.category, AstropyWarning):
             for i, message_to_find in enumerate(messages_to_find):
                 if message_to_find in str(w.message):

diff --git a/astropy/coordinates/tests/test_regression.py b/astropy/coordinates/tests/test_regression.py
@@ -19,7 +19,7 @@
 from ...time import Time
 from ...utils import iers
 
-from ...tests.helper import pytest, assert_quantity_allclose
+from ...tests.helper import pytest, assert_quantity_allclose, catch_warnings
 from .test_matching import HAS_SCIPY, OLDER_SCIPY
 
 
@@ -182,7 +182,7 @@ def test_regression_4210():
         eclobj.distance
 
 
-def test_regression_futuretimes_4302(recwarn):
+def test_regression_futuretimes_4302():
     """
     Checks that an error is not raised for future times not covered by IERS
     tables (at least in a simple transform like CIRS->ITRS that simply requires
@@ -198,14 +198,14 @@ def test_regression_futuretimes_4302(recwarn):
     if hasattr(utils, '__warningregistry__'):
         utils.__warningregistry__.clear()
 
-    future_time = Time('2511-5-1')
-
-    c = CIRS(1*u.deg, 2*u.deg, obstime=future_time)
-    c.transform_to(ITRS(obstime=future_time))
+    with catch_warnings() as found_warnings:
+        future_time = Time('2511-5-1')
+        c = CIRS(1*u.deg, 2*u.deg, obstime=future_time)
+        c.transform_to(ITRS(obstime=future_time))
 
     if not isinstance(iers.IERS_Auto.iers_table, iers.IERS_Auto):
         saw_iers_warnings = False
-        for w in recwarn.list:
+        for w in found_warnings:
             if issubclass(w.category, AstropyWarning):
                 if '(some) times are outside of range covered by IERS table' in str(w.message):
                     saw_iers_warnings = True

diff --git a/astropy/cosmology/core.py b/astropy/cosmology/core.py
@@ -801,7 +801,7 @@ def _w_integrand(self, ln1pz):
         return 1.0 + self.w(z)
 
     def de_density_scale(self, z):
-        """ Evaluates the redshift dependence of the dark energy density.
+        r""" Evaluates the redshift dependence of the dark energy density.
 
         Parameters
         ----------
@@ -815,13 +815,13 @@ def de_density_scale(self, z):
 
         Notes
         -----
-        The scaling factor, I, is defined by :math:`\\rho(z) = \\rho_0 I`,
+        The scaling factor, I, is defined by :math:`\rho(z) = \rho_0 I`,
         and is given by
 
         .. math::
 
-            I = \\exp \\left( 3 \int_{a}^1 \\frac{ da^{\\prime} }{ a^{\\prime} }
-            \\left[ 1 + w\\left( a^{\\prime} \\right) \\right] \\right)
+            I = \exp \left( 3 \int_{a}^1 \frac{ da^{\prime} }{ a^{\prime} }
+            \left[ 1 + w\left( a^{\prime} \right) \right] \right)
 
         It will generally helpful for subclasses to overload this method if
         the integral can be done analytically for the particular dark
@@ -2367,7 +2367,7 @@ def w(self, z):
         return self._w0 + self._wa * z / (1.0 + z)
 
     def de_density_scale(self, z):
-        """ Evaluates the redshift dependence of the dark energy density.
+        r""" Evaluates the redshift dependence of the dark energy density.
 
         Parameters
         ----------
@@ -2386,8 +2386,8 @@ def de_density_scale(self, z):
 
         .. math::
 
-          I = \\left(1 + z\\right)^{3 \\left(1 + w_0 + w_a\\right)}
-          \exp \\left(-3 w_a \\frac{z}{1+z}\\right)
+          I = \left(1 + z\right)^{3 \left(1 + w_0 + w_a\right)}
+          \exp \left(-3 w_a \frac{z}{1+z}\right)
 
         """
         if isiterable(z):
@@ -2651,7 +2651,7 @@ def w(self, z):
         return self._wp + self._wa * (apiv - 1.0 / (1. + z))
 
     def de_density_scale(self, z):
-        """ Evaluates the redshift dependence of the dark energy density.
+        r""" Evaluates the redshift dependence of the dark energy density.
 
         Parameters
         ----------
@@ -2670,10 +2670,10 @@ def de_density_scale(self, z):
 
         .. math::
 
-          a_p = \\frac{1}{1 + z_p}
+          a_p = \frac{1}{1 + z_p}
 
-          I = \\left(1 + z\\right)^{3 \\left(1 + w_p + a_p w_a\\right)}
-          \exp \\left(-3 w_a \\frac{z}{1+z}\\right)
+          I = \left(1 + z\right)^{3 \left(1 + w_p + a_p w_a\right)}
+          \exp \left(-3 w_a \frac{z}{1+z}\right)
         """
 
         if isiterable(z):
@@ -2825,7 +2825,7 @@ def w(self, z):
         return self._w0 + self._wz * z
 
     def de_density_scale(self, z):
-        """ Evaluates the redshift dependence of the dark energy density.
+        r""" Evaluates the redshift dependence of the dark energy density.
 
         Parameters
         ----------
@@ -2844,8 +2844,8 @@ def de_density_scale(self, z):
 
         .. math::
 
-          I = \\left(1 + z\\right)^{3 \\left(1 + w_0 - w_z\\right)}
-          \exp \\left(-3 w_z z\\right)
+          I = \left(1 + z\right)^{3 \left(1 + w_0 - w_z\right)}
+          \exp \left(-3 w_z z\right)
         """
 
         if isiterable(z):

diff --git a/astropy/io/ascii/basic.py b/astropy/io/ascii/basic.py
@@ -41,7 +41,7 @@ class BasicData(core.BaseData):
 
 
 class Basic(core.BaseReader):
-    """
+    r"""
     Read a character-delimited table with a single header line at the top
     followed by data lines to the end of the table.  Lines beginning with # as
     the first non-whitespace character are comments.  This reader is highly

diff --git a/astropy/io/ascii/core.py b/astropy/io/ascii/core.py
@@ -392,7 +392,7 @@ def process_line(self, line):
         """Remove whitespace at the beginning or end of line.  This is especially useful for
         whitespace-delimited files to prevent spurious columns at the beginning or end.
         If splitting on whitespace then replace unquoted tabs with space first"""
-        if self.delimiter == '\s':
+        if self.delimiter == r'\s':
             line = _replace_tab_with_space(line, self.escapechar, self.quotechar)
         return line.strip()
 
@@ -420,7 +420,7 @@ def __call__(self, lines):
         quotechar = None if self.quotechar is None else str(self.quotechar)
         delimiter = None if self.delimiter is None else str(self.delimiter)
 
-        if delimiter == '\s':
+        if delimiter == r'\s':
             delimiter = ' '
 
         csv_reader = csv.reader(lines,

diff --git a/astropy/io/ascii/daophot.py b/astropy/io/ascii/daophot.py
@@ -29,7 +29,7 @@ class DaophotHeader(core.BaseHeader):
     comment = r'\s*#K'
 
     # Regex for extracting the format strings
-    re_format = re.compile('%-?(\d+)\.?\d?[sdfg]')
+    re_format = re.compile(r'%-?(\d+)\.?\d?[sdfg]')
     re_header_keyword = re.compile(r'[#]K'
                                    r'\s+ (?P<name> \w+)'
                                    r'\s* = (?P<stuff> .+) $',

diff --git a/astropy/io/ascii/ipac.py b/astropy/io/ascii/ipac.py
@@ -237,7 +237,7 @@ def str_vals(self):
                                   'This causes duplicate column names: {0}'.format(doublenames))
 
         for name in namelist:
-            m = re.match('\w+', name)
+            m = re.match(r'\w+', name)
             if m.end() != len(name):
                 raise IpacFormatE('{0} - Only alphanumeric characters and _ '
                                   'are allowed in column names.'.format(name))
@@ -324,7 +324,7 @@ def write(self, lines, widths, vals_list):
 
 
 class Ipac(basic.Basic):
-    """Read or write an IPAC format table.  See
+    r"""Read or write an IPAC format table.  See
     http://irsa.ipac.caltech.edu/applications/DDGEN/Doc/ipac_tbl.html::
 
       \\name=value

diff --git a/astropy/io/ascii/latex.py b/astropy/io/ascii/latex.py
@@ -326,7 +326,7 @@ def write(self, table=None):
 
 
 class AASTexHeaderSplitter(LatexSplitter):
-    '''Extract column names from a `deluxetable`_.
+    r'''Extract column names from a `deluxetable`_.
 
     This splitter expects the following LaTeX code **in a single line**:
 
@@ -352,7 +352,7 @@ def join(self, vals):
 
 
 class AASTexHeader(LatexHeader):
-    '''In a `deluxetable
+    r'''In a `deluxetable
     <http://fits.gsfc.nasa.gov/standard30/deluxetable.sty>`_ some header
     keywords differ from standard LaTeX.
 
@@ -387,7 +387,7 @@ def write(self, lines):
 
 
 class AASTexData(LatexData):
-    '''In a `deluxetable`_ the data is enclosed in `\startdata` and `\enddata`
+    r'''In a `deluxetable`_ the data is enclosed in `\startdata` and `\enddata`
     '''
     data_start = r'\startdata'
     data_end = r'\enddata'

diff --git a/astropy/io/ascii/tests/test_read.py b/astropy/io/ascii/tests/test_read.py
@@ -770,7 +770,7 @@ def get_testfiles(name=None):
         {'name': 't/whitespace.dat',
          'cols': ('quoted colname with tab\tinside', 'col2', 'col3'),
          'nrows': 2,
-         'opts': {'delimiter': '\s'}},
+         'opts': {'delimiter': r'\s'}},
         {'name': 't/simple_csv.csv',
          'cols': ('a','b','c'),
          'nrows': 2,

diff --git a/astropy/io/ascii/tests/test_write.py b/astropy/io/ascii/tests/test_write.py
@@ -570,8 +570,8 @@ def test_latex_units():
     out = StringIO()
     ascii.write(t, out, format='aastex', latexdict=ascii.latexdicts['AA'])
     assert out.getvalue() == expected.replace(
-        'colhead{s}', 'colhead{$\mathrm{s}$}').replace(
-        'colhead{ }', 'colhead{$\mathrm{yr}$}')
+        'colhead{s}', r'colhead{$\mathrm{s}$}').replace(
+        'colhead{ }', r'colhead{$\mathrm{yr}$}')
 
 
 @pytest.mark.parametrize("fast_writer", [True, False])