assertEquals在两个看似相同的字符串上失败了

Question

这是我的测试：

@Test
public void testAddPaperConfirm()
{
    String input = "P\n" +
                    "The Life of Geoff the Platypus";
    InputStream testInput = new ByteArrayInputStream(input.getBytes());
    System.setOut(new PrintStream(testOutput));
    System.setIn(testInput);
    testReviewSystem.main(new String[] {});
    assertEquals(testOutput.toString(), "What do you want to do?\n" +
            "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\n" +
            "What is the title of the paper?\n" +
            "[Paper added]\n"
            + "What do you want to do?\n" +
            "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\n");
}

当我看到这两个字符串时，我被告知它们是相同的。

Answer 1

失败是因为它们不相同。

看起来相同的两个字符串可能不同。有许多字节无法表示和显示。

例如ascii代码0和ascii代码1，它们看起来完全相同，但它们不是。

http://www.ascii-code.com/

Answer 2

我认为您在Windows上运行测试并输出\r\n而不是\n作为行分隔符。您可以通过将断言更改为以下代码来尝试此操作。

assertEquals(testOutput.toString(), "What do you want to do?\r\n" +
        "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\r\n" +
        "What is the title of the paper?\r\n" +
        "[Paper added]\r\n"
        + "What do you want to do?\r\n" +
        "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\r\n")

我编写了一个名为System Rules的测试库，可以更轻松地测试命令行应用程序。

public class TheTest {
  @Rule
  public final TextFromStandardInputStream systemInMock
    = emptyStandardInputStream();
  @Rule
  public final SystemOutRule systemOutRule
    = new SystemOutRule().enableLog();

  @Test
  public void testAddPaperConfirm() {
    systemInMock.provideLines("P", "The Life of Geoff the Platypus");
    testReviewSystem.main(new String[] {});
    String output = systemOutRule.getLogWithNormalizedLineSeparator();
    assertEquals(output, "What do you want to do?\n" +
        "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\n" +
        "What is the title of the paper?\n" +
        "[Paper added]\n"
        + "What do you want to do?\n" +
        "O = Overview, P = Add Paper, R = Add Review, [num] = Detail of that paper, X = exit\n");
  }
}