@Test public void testCalculateBufferLength() throws Exception { final Method calculateBufferLengthMethod = Whitebox.getMethod(AuditEventDefaultFormatter.class, "calculateBufferLength", AuditEvent.class, int.class); final LocalizedMessage localizedMessage = new LocalizedMessage(1, 1, "messages.properties", "key", null, SeverityLevel.ERROR, null, getClass(), null); final AuditEvent auditEvent = new AuditEvent(new Object(), "fileName", localizedMessage); final int result = (int) calculateBufferLengthMethod.invoke(null, auditEvent, SeverityLevel.ERROR.ordinal()); assertEquals("Buffer length is not expected", 54, result); }