Add test for scheme relative uris

Author: slandelle

client/src/test/java/org/asynchttpclient/uri/UriTest.java

@@ -228,6 +228,19 @@ public void testRelativeUriWithConsecutiveDotsFromLevel3Resource() {
         assertNull(url.getQuery());
     }
 
+    @Test
+    public void testRelativeUriWithNoScheme() {
+        Uri context = Uri.create("https://hello.com/level1");
+
+        Uri url = Uri.create(context, "//world.org/content/img.png");
+
+        assertEquals(url.getScheme(), "https");
+        assertEquals(url.getHost(), "world.org");
+        assertEquals(url.getPort(), -1);
+        assertEquals(url.getPath(), "/content/img.png");
+        assertNull(url.getQuery());
+    }
+
     @Test
     public void testCreateAndToUrl() {
         String url = "https://hello.com/level1/level2/level3";