### Question:
FileAuthorizer extends AbstractPolicyBasedAuthorizer { @Override public synchronized User deleteUser(final User user) throws AuthorizationAccessException { return userGroupProvider.deleteUser(user); }  @Override void initialize(final AuthorizerInitializationContext initializationContext); @Override void doOnConfigured(final AuthorizerConfigurationContext configurationContext); @Override void preDestruction(); @Override synchronized Group doAddGroup(Group group); @Override Group getGroup(String identifier); @Override synchronized Group doUpdateGroup(Group group); @Override synchronized Group deleteGroup(Group group); @Override Set<Group> getGroups(); @Override synchronized User doAddUser(final User user); @Override User getUser(final String identifier); @Override User getUserByIdentity(final String identity); @Override synchronized User doUpdateUser(final User user); @Override synchronized User deleteUser(final User user); @Override Set<User> getUsers(); @Override synchronized AccessPolicy doAddAccessPolicy(final AccessPolicy accessPolicy); @Override AccessPolicy getAccessPolicy(final String identifier); @Override synchronized AccessPolicy updateAccessPolicy(final AccessPolicy accessPolicy); @Override synchronized AccessPolicy deleteAccessPolicy(final AccessPolicy accessPolicy); @Override Set<AccessPolicy> getAccessPolicies(); @AuthorizerContext void setNiFiProperties(NiFiProperties properties); @Override synchronized UsersAndAccessPolicies getUsersAndAccessPolicies();  }### Answer:
@Test public void testDeleteUser() throws Exception { writeFile(primaryAuthorizations, AUTHORIZATIONS); writeFile(primaryTenants, TENANTS); authorizer.onConfigured(configurationContext); assertEquals(2, authorizer.getUsers().size()); final User user = authorizer.getUser("user-1"); assertEquals("user-1", user.getIdentifier()); final User deletedUser = authorizer.deleteUser(user); assertNotNull(deletedUser); assertEquals("user-1", deletedUser.getIdentifier()); assertEquals(1, authorizer.getUsers().size()); assertNull(authorizer.getUser(user.getIdentifier())); }