xref: /aosp_15_r20/external/antlr/runtime/Python3/tests/t001lexer.py (revision 16467b971bd3e2009fad32dd79016f2c7e421deb)

import antlr3
import testbase
import unittest

class t001lexer(testbase.ANTLRTest):
    def setUp(self):
        self.compileGrammar()


    def lexerClass(self, base):
        class TLexer(base):
            def emitErrorMessage(self, msg):
                # report errors to /dev/null
                pass

            def reportError(self, re):
                # no error recovery yet, just crash!
                raise re

        return TLexer


    def testValid(self):
        stream = antlr3.StringStream('0')
        lexer = self.getLexer(stream)

        token = lexer.nextToken()
        self.assertEqual(token.type, self.lexerModule.ZERO)

        token = lexer.nextToken()
        self.assertEqual(token.type, self.lexerModule.EOF)


    def testIteratorInterface(self):
        stream = antlr3.StringStream('0')
        lexer = self.getLexer(stream)

        types = [token.type for token in lexer]

        self.assertEqual(types, [self.lexerModule.ZERO])


    def testMalformedInput(self):
        stream = antlr3.StringStream('1')
        lexer = self.getLexer(stream)

        try:
            token = lexer.nextToken()
            self.fail()

        except antlr3.MismatchedTokenException as exc:
            self.assertEqual(exc.expecting, '0')
            self.assertEqual(exc.unexpectedType, '1')


if __name__ == '__main__':
    unittest.main()