bpo-33305: Improve SyntaxError for invalid numerical literals. (GH-6517)

1 files changed, 24 insertions, 0 deletions

diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index ee41362..78918ae 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -100,6 +100,8 @@ INVALID_UNDERSCORE_LITERALS = [
 
 class TokenTests(unittest.TestCase):
 
+    check_syntax_error = check_syntax_error
+
     def test_backslash(self):
         # Backslash means line continuation:
         x = 1 \
@@ -184,6 +186,28 @@ class TokenTests(unittest.TestCase):
         # Sanity check: no literal begins with an underscore
         self.assertRaises(NameError, eval, "_0")
 
+    def test_bad_numerical_literals(self):
+        check = self.check_syntax_error
+        check("0b12", "invalid digit '2' in binary literal")
+        check("0b1_2", "invalid digit '2' in binary literal")
+        check("0b2", "invalid digit '2' in binary literal")
+        check("0b1_", "invalid binary literal")
+        check("0b", "invalid binary literal")
+        check("0o18", "invalid digit '8' in octal literal")
+        check("0o1_8", "invalid digit '8' in octal literal")
+        check("0o8", "invalid digit '8' in octal literal")
+        check("0o1_", "invalid octal literal")
+        check("0o", "invalid octal literal")
+        check("0x1_", "invalid hexadecimal literal")
+        check("0x", "invalid hexadecimal literal")
+        check("1_", "invalid decimal literal")
+        check("012",
+              "leading zeros in decimal integer literals are not permitted; "
+              "use an 0o prefix for octal integers")
+        check("1.2_", "invalid decimal literal")
+        check("1e2_", "invalid decimal literal")
+        check("1e+", "invalid decimal literal")
+
     def test_string_literals(self):
         x = ''; y = ""; self.assertTrue(len(x) == 0 and x == y)
         x = '\''; y = "'"; self.assertTrue(len(x) == 1 and x == y and ord(x) == 39)