public boolean isGenerateCalled() {
            return generateCalled;
        }

        public boolean isDestroyCalled() {
            return destroyCalled;
        }
    }

    public void test_isAvailable() {
        // Test default implementation
        generator = new TestThumbnailGenerator();
        assertTrue(generator.isAvailable());
    }

    public void test_isTarget() {
        // Test isTarget method

        emptyGenerator.destroy();
        // Call destroy multiple times to ensure it's safe
        emptyGenerator.destroy();
        emptyGenerator.destroy();
    }

    public void test_isAvailable() {
        // Initialize without container
        emptyGenerator = new EmptyGenerator();

        // Test that isAvailable returns true for EmptyGenerator
        assertTrue(emptyGenerator.isAvailable());

        Map<String, Object> docMap = new HashMap<>();
        docMap.put("mimetype", null);
        assertFalse(thumbnailGenerator.isTarget(docMap));
    }

    public void test_isAvailable() {
        // Test availability check
        assertTrue(thumbnailGenerator.isAvailable());
    }

    public void test_destroy() {
        // Test destroy method - should not throw exception