Minimal JUnit test setup with security context and a mocked user

MinimalMockUserTest.java

    @Test
    void testMethod() throws Exception {
        SecurityContextHolder.setContext(
                SecurityContextHolder.createEmptyContext()
        );
        SecurityContextHolder.getContext().setAuthentication(
                new TestingAuthenticationToken("TEST_USER", null)
        );
    }

Also see https://gist.github.com/BjoernKW/0b9cb56dd3884a8bbbebedb6cc77718f and this code snippet using that factory:

    private static final String TEST_USER = "TEST_USER";

    @Test
    void recipientListEntryReceivedEvent() throws Exception {
        SecurityContextFactory.createSecurityContext(TEST_USER);
    }