DefaultBootLogger implements BootLogger { @Override public void stdout(String message) { stdout.println(message); } DefaultBootLogger(boolean trace);  DefaultBootLogger(boolean trace, PrintStream stdout, PrintStream stderr); @Override void trace(Supplier<String> messageSupplier); @Override void stdout(String message); @Override void stderr(String message); @Override void stderr(String message, Throwable th);  }
@Test public void testStdout() { DefaultBootLogger logger = new DefaultBootLogger(true, mockStdout, mockStderr); logger.stdout("outmsg"); verify(mockStdout).println("outmsg"); verifyNoInteractions(mockStderr); }