Fixed the crash error as token_string was not defined #125

Signed-off-by: Chin Yeung Li <tli@nexb.com>

Author: chinyeungli

src/license_expression/__init__.py

@@ -87,7 +87,9 @@
 
 
 class ExpressionError(Exception):
-    pass
+    def __init__(self, message, token_string=None):
+        super().__init__(message)
+        self.token_string = token_string
 
 
 class ExpressionParseError(ParseError, ExpressionError):
@@ -1210,7 +1212,8 @@ def __init__(
             raise ExpressionError(
                 "Invalid license key: the valid characters are: letters and "
                 "numbers, underscore, dot, colon or hyphen signs and "
-                f"spaces: {key!r}"
+                f"spaces: {key!r}",
+                token_string=f"{key!r}",
             )
 
         # normalize spaces
@@ -1219,7 +1222,8 @@ def __init__(
         if key.lower() in KEYWORDS_STRINGS:
             raise ExpressionError(
                 'Invalid license key: a key cannot be a reserved keyword: "or",'
-                f' "and" or "with": {key!r}'
+                f' "and" or "with": {key!r}',
+                token_string=f"{key!r}",
             )
 
         self.key = key

tests/test_license_expression.py

@@ -2422,6 +2422,15 @@ def test_validation_invalid_license_key(self):
         assert result.errors == ["Unknown license key(s): cool-license"]
         assert result.invalid_symbols == ["cool-license"]
 
+    def test_validation_invalid_license_key_chara(self):
+        result = self.licensing.validate("cool,license")
+        assert result.original_expression == "cool,license"
+        assert not result.normalized_expression
+        assert result.errors == [
+            "Invalid license key: the valid characters are: letters and numbers, underscore, dot, colon or hyphen signs and spaces: 'cool,license'"
+        ]
+        assert result.invalid_symbols == ["'cool,license'"]
+
     def test_validate_exception(self):
         result = self.licensing.validate("GPL-2.0-or-later WITH WxWindows-exception-3.1")
         assert result.original_expression == "GPL-2.0-or-later WITH WxWindows-exception-3.1"