JUnit asserting two Strings whether they're equal or not

问题

So I looked up this question and tried it, but with no success.

My code should be testing if the method is correctly outputing the text onto the console by reading it back in using Streams.

    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    PrintStream myStream = new PrintStream(outStream);
    System.setOut(myStream);
    o.doSomething(); //printing out Hi
    System.out.flush();
    System.setOut(savedOldStream);//setting it back to System.out
    assertEquals(outStream.toString(),"Hi");

but everytime I run JUnit it fails. I also tried: assertTrue(outStream.toString().equals("Hi")); but this didn't work either.

This is the doSomething() method:

public void doSomething () {
    System.out.println("Hi");
}

回答1:

PrintStream#println(String str) appends a newline at the end of the string. Therefore, your assertion should trim down the additional line:

assertEquals(outStream.toString().trim(),"Hi");

来源：https://stackoverflow.com/questions/30579868/junit-asserting-two-strings-whether-theyre-equal-or-not