@Override
    public NSImage documentIcon(final String extension, final Integer size) {
        NSImage image = this.load(extension, size);
        if(null == image) {
            return this.cache(extension,
                    this.convert(extension, workspace.iconForFileType(extension), size), size);
        }
        return image;
    }
@Test
    public void testDocumentIconNoExtension() {
        final NSImage icon = new NSImageIconCache().documentIcon("", 64);
        assertNotNull(icon);
        assertTrue(icon.isValid());
        assertFalse(icon.isTemplate());
        assertEquals(64, icon.size().width.intValue());
        assertEquals(64, icon.size().height.intValue());
    }