testProp = new Properties(System.getProperties());
    String override = "test\njava.version : hidden";

    testProp.load(new StringReader(override));

    result = Maps.fromProperties(testProp);
    assertTrue(result.size() > 2);
    assertEquals("", result.get("test"));
    assertEquals("hidden", result.get("java.version"));
    assertNotSame(System.getProperty("java.version"), result.get("java.version"));