fix for GRAILS-6532 "JSONObject.containsKey() is broken"

src/java/org/codehaus/groovy/grails/web/json/JSONObject.java

@@ -1157,11 +1157,11 @@ public boolean isEmpty() {
     }
 
     public boolean containsKey(Object o) {
-        return false;
+        return myHashMap.containsKey(o);
     }
 
     public boolean containsValue(Object o) {
-        return this.myHashMap.containsKey(o);
+        return this.myHashMap.containsValue(o);
     }
 
     public Object get(Object o) {

src/test/org/codehaus/groovy/grails/web/json/JSONObjectTests.groovy

@@ -0,0 +1,22 @@
+package org.codehaus.groovy.grails.web.json
+
+/**
+ * @author Graeme Rocher
+ * @since 1.0
+ */
+class JSONObjectTests extends GroovyTestCase {
+
+
+    void testContainsKey() {
+        JSONObject j = new JSONObject();
+        j.put('test', 1)
+        assert j.containsKey('test')
+    }
+
+    void testContainsValue() {
+        JSONObject j = new JSONObject();
+        j.put('test', 1)
+        assert j.containsValue(1)
+
+    }
+}