public function testZeroFill() { $this->assertEquals('0000', StringUtils::zeroFill('')); $this->assertEquals('0001', StringUtils::zeroFill('1')); $this->assertEquals('0010', StringUtils::zeroFill(10)); $this->assertEquals('123123', StringUtils::zeroFill('123123')); $this->assertEquals('00ab', StringUtils::zeroFill('ab')); $this->assertEquals('000ab', StringUtils::zeroFill('ab', 5)); $this->assertEquals('000000123456', StringUtils::zeroFill('123456', 12)); }