}

    @Test
    public void test_expandPath() {
        // Test expandPath method
        generator = new TestThumbnailGenerator();

        // Test without mappings
        assertEquals("path/to/file", generator.expandPath("path/to/file"));
        assertNull(generator.expandPath(null));

        // Test with exact match mappings (expandPath only replaces exact matches)

    /**
     * Expands a file path using the file path mapping.
     * @param value The original path value.
     * @return The expanded path or the original value if no mapping exists.
     */
    protected String expandPath(final String value) {
        if (value != null && filePathMap.containsKey(value)) {
            return filePathMap.get(value);
        }
        return value;
    }

    /**

                final String outputPath = outputFile.getAbsolutePath();
                final List<String> cmdList = new ArrayList<>();
                for (final String value : commandList) {
                    cmdList.add(expandPath(value.replace("${url}", tempPath)
                            .replace("${outputFile}", outputPath)
                            .replace("${mimetype}", mimeType != null ? mimeType : "")));
                }

        assertTrue("Long commands should be settable", true);
    }

    // Test path expansion logic
    @Test
    public void test_path_expansion() throws Exception {
        // Test the expandPath functionality indirectly through variable replacement
        final String testCommand = "convert ${url} -resize 100x100 ${outputFile}";
        final String tempPath = "/tmp/source.pdf";

        assertEquals("test/path", emptyGenerator.expandPath("test/path"));
        assertNull(emptyGenerator.expandPath(null));

        // Test with file path mappings
        emptyGenerator.filePathMap.put("${path}/test", "/usr/bin/test");
        assertEquals("/usr/bin/test", emptyGenerator.expandPath("${path}/test"));
        assertEquals("other/path", emptyGenerator.expandPath("other/path"));
    }

    @Test