@Override
    public void release(final ConnectionSession connectionSession) {
        PostgreSQLPortalContextRegistry.getInstance().remove(connectionSession.getConnectionId());
    }
@Test
    void assertRelease() {
        ConnectionSession connectionSession = mock(ConnectionSession.class, RETURNS_DEEP_STUBS);
        int connectionId = 1;
        when(connectionSession.getConnectionId()).thenReturn(connectionId);
        PostgreSQLPortalContextRegistry.getInstance().get(connectionId);
        PostgreSQLFrontendEngine frontendEngine = new PostgreSQLFrontendEngine();
        ConnectionThreadExecutorGroup.getInstance().register(connectionId);
        ConnectionThreadExecutorGroup.getInstance().unregisterAndAwaitTermination(connectionId);
        frontendEngine.release(connectionSession);
        assertTrue(getPortalContexts().isEmpty());
    }