Improved coverage of mathtext and removed unused code

Author: oscargus

lib/matplotlib/_mathtext.py

@@ -1954,7 +1954,6 @@ def __init__(self):
         p.auto_delim       = Forward()
         p.binom            = Forward()
         p.bslash           = Forward()
-        p.c_over_c         = Forward()
         p.customspace      = Forward()
         p.end_group        = Forward()
         p.float_literal    = Forward()
@@ -2031,11 +2030,6 @@ def __init__(self):
 
         p.apostrophe    <<= Regex("'+")
 
-        p.c_over_c      <<= (
-            Suppress(p.bslash)
-            + oneOf(list(self._char_over_chars))
-        )
-
         p.accent        <<= Group(
             Suppress(p.bslash)
             + oneOf([*self._accent_map, *self._wide_accents])
@@ -2138,7 +2132,6 @@ def __init__(self):
             | p.accent   # Must be before symbol as all accents are symbols
             | p.symbol   # Must be third to catch all named symbols and single
                          # chars not in a group
-            | p.c_over_c
             | p.function
             | p.group
             | p.frac
@@ -2375,50 +2368,6 @@ def unknown_symbol(self, s, loc, toks):
         c, = toks
         raise ParseFatalException(s, loc, "Unknown symbol: %s" % c)
 
-    _char_over_chars = {
-        # The first 2 entries in the tuple are (font, char, sizescale) for
-        # the two symbols under and over.  The third element is the space
-        # (in multiples of underline height)
-        r'AA': (('it', 'A', 1.0), (None, '\\circ', 0.5), 0.0),
-    }
-
-    def c_over_c(self, s, loc, toks):
-        sym, = toks
-        state = self.get_state()
-        thickness = state.font_output.get_underline_thickness(
-            state.font, state.fontsize, state.dpi)
-
-        under_desc, over_desc, space = \
-            self._char_over_chars.get(sym, (None, None, 0.0))
-        if under_desc is None:
-            raise ParseFatalException("Error parsing symbol")
-
-        over_state = state.copy()
-        if over_desc[0] is not None:
-            over_state.font = over_desc[0]
-        over_state.fontsize *= over_desc[2]
-        over = Accent(over_desc[1], over_state)
-
-        under_state = state.copy()
-        if under_desc[0] is not None:
-            under_state.font = under_desc[0]
-        under_state.fontsize *= under_desc[2]
-        under = Char(under_desc[1], under_state)
-
-        width = max(over.width, under.width)
-
-        over_centered = HCentered([over])
-        over_centered.hpack(width, 'exactly')
-
-        under_centered = HCentered([under])
-        under_centered.hpack(width, 'exactly')
-
-        return Vlist([
-                over_centered,
-                Vbox(0., thickness * space),
-                under_centered
-                ])
-
     _accent_map = {
         r'hat':            r'\circumflexaccent',
         r'breve':          r'\combiningbreve',

lib/matplotlib/_mathtext_data.py

@@ -1116,6 +1116,7 @@
     'cwopencirclearrow'        : 8635,
     'geqq'                     : 8807,
     'rightleftarrows'          : 8644,
+    'aa'                       : 229,
     'ac'                       : 8766,
     'ae'                       : 230,
     'int'                      : 8747,

lib/matplotlib/tests/test_mathtext.py

@@ -257,6 +257,11 @@ def test_fontinfo():
         (r'$\dfrac{}{}$', r'Expected \dfrac{num}{den}'),
         (r'$\overset$', r'Expected \overset{body}{annotation}'),
         (r'$\underset$', r'Expected \underset{body}{annotation}'),
+        (r'$\foo$', r'Unknown symbol: \foo'),
+        (r'$a^2^2$', r'Double superscript'),
+        (r'$a_2_2$', r'Double subscript'),
+        (r'$a^2_a^2$', r'Subscript/superscript sequence is too long.'\
+            r' Use braces { } to remove ambiguity.'),
     ],
     ids=[
         'hspace without value',
@@ -279,6 +284,10 @@ def test_fontinfo():
         'dfrac with empty parameters',
         'overset without parameters',
         'underset without parameters',
+        'unknown symbol',
+        'double superscript',
+        'double subscript',
+        'super on sub without braces'
     ]
 )
 def test_mathtext_exceptions(math, msg):
@@ -288,6 +297,11 @@ def test_mathtext_exceptions(math, msg):
         parser.parse(math)
 
 
+def test_get_unicode_index_exception():
+    with pytest.raises(ValueError):
+        _mathtext.get_unicode_index(r'\foo')
+
+
 def test_single_minus_sign():
     plt.figure(figsize=(0.3, 0.3))
     plt.text(0.5, 0.5, '$-$')