@Test
void testAppendLine() throws IOException {

    BufferedReader reader = bufferedReaderBuilder
            .appendLine(firstTestString)
            .appendLine(secondTestString)
            .appendLine(thirdTestString)
            .build();
    Assertions.assertEquals(reader.readLine(), firstTestString);
    Assertions.assertEquals(reader.readLine(), secondTestString);
    Assertions.assertEquals(reader.readLine(), thirdTestString);
}