Spring – Access to h2 web console while running junit test in a Spring application

using ByteArrayOutputStream and System.setXXX is simple:

private final ByteArrayOutputStream outContent = new ByteArrayOutputStream();
private final ByteArrayOutputStream errContent = new ByteArrayOutputStream();
private final PrintStream originalOut = System.out;
private final PrintStream originalErr = System.err;

@Before
public void setUpStreams() {
    System.setOut(new PrintStream(outContent));
    System.setErr(new PrintStream(errContent));
}

@After
public void restoreStreams() {
    System.setOut(originalOut);
    System.setErr(originalErr);
}

sample test cases:

@Test
public void out() {
    System.out.print("hello");
    assertEquals("hello", outContent.toString());
}

@Test
public void err() {
    System.err.print("hello again");
    assertEquals("hello again", errContent.toString());
}

I used this code to test the command line option (asserting that -version outputs the version string, etc etc)

Edit: Prior versions of this answer called System.setOut(null) after the tests; This is the cause of NullPointerExceptions commenters refer to.

My mistake, the resource files WERE actually copied to target/test-classes. The problem seemed to be due to spaces in my project name, e.g. Project%20Name.

I'm now loading the file as follows and it works:

org.apache.commons.io.FileUtils.toFile(myClass().getResource("resourceFile.txt")‌​);

Or, (taken from Java: how to get a File from an escaped URL?) this may be better (no dependency on Apache Commons):

myClass().getResource("resourceFile.txt")‌​.toURI();