### Question:
ExpandableUrl { private static String collapseEnvVars(String path){ String pluginDir = unifySlashes(Directories.getXdgJrdBaseDir()); String homeDir = unifySlashes(System.getProperty("user.home")); String jrdDir = unifySlashes(getJrdLocation()); return collapseEnvVars(unifySlashes(path), homeDir, pluginDir, jrdDir); } private  ExpandableUrl(String s); static ExpandableUrl createFromPath(String path); static ExpandableUrl createFromStringUrl(String url); static String unifySlashes(String dir); static boolean isOsWindows(); URL getExpandedURL(); String getRawURL(); String getExpandedPath(); String getRawPath(); File getFile(); @Override String toString();  }### Answer:
@Test void testCollapseEnvVars() { assertEquals("${HOME}", collapseEnvVars("home_path", "home_path", "config_path", "jrd_path")); assertEquals("${XDG_CONFIG_HOME}", collapseEnvVars("config_path", "home_path", "config_path", "jrd_path")); assertEquals("${JRD}", collapseEnvVars("jrd_path", "home_path", "config_path", "jrd_path")); assertEquals("${HOME}", collapseEnvVars("${HOME}", "home_path", "config_path", "jrd_path")); assertEquals("different_path", collapseEnvVars("different_path", "home_path", "config_path", "jrd_path")); assertEquals("/${HOME}", collapseEnvVars("/home_path", "home_path", "config_path", "jrd_path")); }