public function testSquareColor() { $chess = new Chess(); $this->assertSame($chess->squareColor('a1'), 'dark'); $this->assertSame($chess->squareColor('b2'), 'dark'); $this->assertSame($chess->squareColor('b3'), 'light'); $this->assertSame($chess->squareColor('e4'), 'light'); $this->assertSame($chess->squareColor('e5'), 'dark'); $this->assertSame($chess->squareColor('aw'), null); }