Test cases for issue described in stleary#410.

Author: John J. Aylward

src/test/java/org/json/junit/JSONPointerTest.java

@@ -62,6 +62,19 @@ public void queryByEmptyKey() {
         assertSame(document.get(""), query("/"));
     }
 
+    @Test
+    public void queryByEmptyKeySubObject() {
+        assertSame(document.getJSONObject("obj").getJSONObject(""), query("/obj/"));
+    }
+
+    @Test
+    public void queryByEmptyKeySubObjectSubOject() {
+        assertSame(
+            document.getJSONObject("obj").getJSONObject("").get(""),
+            query("/obj//")
+        );
+    }
+
     @Test
     public void slashEscaping() {
         assertSame(document.get("a/b"), query("/a~1b"));

src/test/resources/jsonpointer-testdoc.json

@@ -19,6 +19,7 @@
 			"another/key" : [
 				"val"
 			]
-		}
+		},
+		"" : { "" : "empty key of an object with an empty key" }
 	}
 }