@Test
public void testLeftShift() throws Exception {

    String text = "a << 3";
    Parser parser = new Parser(text);
    AstExpr expr = parser.expr();
    
    AstBinary binaryExpr = (AstBinary) expr;
    
    AstIdentifier left = (AstIdentifier) binaryExpr.getLeft();
    AstNumber right = (AstNumber) binaryExpr.getRight();
    
    assertEquals("a", left.getName());
    assertEquals(3, right.getValue());
    assertEquals(expr.toString(), text);
}