Update test_latex.py to match {} around \ldots

IPython/nbconvert/filters/tests/test_latex.py

@@ -31,7 +31,7 b' class TestLatex(TestsBase):'
             (r'How are \you doing today?', r'How are \textbackslash{}you doing today?'),
             (r'\escapechar=`\A\catcode`\|=0 |string|foo', r'\textbackslash{}escapechar=`\textbackslash{}A\textbackslash{}catcode`\textbackslash{}|=0 |string|foo'),
             (r'# $ % & ~ _ ^ \ { }', r'\# \$ \% \& \textasciitilde{} \_ \^{} \textbackslash{} \{ \}'),
-            ('...', r'\ldots'),
+            ('...', r'{\ldots}'),
             ('','')]
 
         for test in tests: