private void definePackageInternal(final String packageName, final Manifest manifest) {
        if (null != getPackage(packageName)) {
            return;
        }
        Attributes attributes = manifest.getMainAttributes();
        String specTitle = attributes.getValue(Attributes.Name.SPECIFICATION_TITLE);
        String specVersion = attributes.getValue(Attributes.Name.SPECIFICATION_VERSION);
        String specVendor = attributes.getValue(Attributes.Name.SPECIFICATION_VENDOR);
        String implTitle = attributes.getValue(Attributes.Name.IMPLEMENTATION_TITLE);
        String implVersion = attributes.getValue(Attributes.Name.IMPLEMENTATION_VERSION);
        String implVendor = attributes.getValue(Attributes.Name.IMPLEMENTATION_VENDOR);
        definePackage(packageName, specTitle, specVersion, specVendor, implTitle, implVersion, implVendor, null);
    }
@Test
    public void testDefinePackageInternal() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException, IOException {
        Method definePackageInternal = ShenyuPluginLoader.class.getDeclaredMethod("definePackageInternal", String.class, Manifest.class);
        definePackageInternal.setAccessible(true);
        Manifest manifest = mock(Manifest.class);
        when(manifest.getMainAttributes()).thenReturn(mock(Attributes.class));
        definePackageInternal.invoke(ShenyuPluginLoader.getInstance(), "org.apache.shenyu.plugin.DividePlugin", manifest);
    }