function testCountGroups()
{
$lexer = new Lexer();
$count = $lexer->countGroups('(');
$this->assertEquals(1, $count);
$count = $lexer->countGroups('(aa)((bb)gg)');
$this->assertEquals(3, $count);
$count = $lexer->countGroups('\\(');
$this->assertEquals(0, $count);
$count = $lexer->countGroups('\\\\(');
$this->assertEquals(1, $count);
$count = $lexer->countGroups('(\\\\()');
$this->assertEquals(2, $count);
$count = $lexer->countGroups('\\(()');
$this->assertEquals(1, $count);
$count = $lexer->countGroups('(?:aaa)');
$this->assertEquals(0, $count);
$count = $lexer->countGroups('aaa(?!bbb)(ccc)+');
$this->assertEquals(1, $count);
$count = $lexer->countGroups('1(2(3(4)*)*)*');
$this->assertEquals(3, $count);
$count = $lexer->countGroups('[-]?(0|[1-9][0-9]*)(\\.[0-9]+)?([eE][+-]?[0-9]+)?');
$this->assertEquals(3, $count);
$count = $lexer->countGroups('"([^"\\\\]|[\\\\](["\\\\/bfnrt]|u[0-9a-z]{4}))*"');
$this->assertEquals(2, $count);
}