// Test generation with null output file
        String thumbnailId = "test-thumbnail-002";
        assertFalse(thumbnailGenerator.generate(thumbnailId, null));
    }

    public void test_generate_withInvalidOutputPath() throws IOException {
        // Test generation with non-writable output file
        File readOnlyDir = Files.createTempDirectory(tempDir, "readonly").toFile();
        readOnlyDir.setWritable(false);