public function testAppendAddsDataToFile() { file_put_contents(__DIR__ . '/file.txt', 'foo'); $files = new Filesystem(); $bytesWritten = $files->append(__DIR__ . '/file.txt', 'bar'); $this->assertEquals(mb_strlen('bar', '8bit'), $bytesWritten); $this->assertFileExists(__DIR__ . '/file.txt'); $this->assertStringEqualsFile(__DIR__ . '/file.txt', 'foobar'); @unlink(__DIR__ . '/file.txt'); }