testFindTokenAtOffset(source, offset, expected, expected);
}
protected void testFindTokenAtOffset(String source, int offset, Token expectedLeft, Token expectedRight) {
LexerResult lexerResult = new LexerResult(source,
new LexElementProducer().produceLexTokens(new DeeLexer(source)));
TokenAtOffsetResult tokenAtOffsetResult = lexerResult.findTokenAtOffset(offset);
if(expectedLeft == expectedRight) {
assertTrue(tokenAtOffsetResult.atLeft == tokenAtOffsetResult.atRight);
}