public static Map<String, String> buildRegionChoices() {
        Map<String, String> regions = Maps.newHashMap();
        for (Regions region : Regions.values()) {

            String displayValue = f("%s: %s", region.getDescription(), region.getName());
            regions.put(region.getName(), displayValue);
        }
        return regions;
    }
@Test
    public void testRegionChoices() {

        Map<String, String> regionChoices = AWS.buildRegionChoices();

        // Check format of random region.
        assertTrue(regionChoices.containsValue("EU (London): eu-west-2"));
        assertTrue(regionChoices.containsKey("eu-west-2"));

        // Verify that the Gov regions are present.
        //"us-gov-west-1" -> "AWS GovCloud (US): us-gov-west-1"
        assertTrue(regionChoices.containsValue("AWS GovCloud (US): us-gov-west-1"));
        assertTrue(regionChoices.containsKey("us-gov-west-1"));
        assertTrue(regionChoices.containsValue("AWS GovCloud (US-East): us-gov-east-1"));
        assertTrue(regionChoices.containsKey("us-gov-east-1"));
    }