[Finishes #52959947] Warn user about spy conflicts; Refactor spy tests to more reflect responsibilities and removed duplicate tests

src/core/Env.js

@@ -211,16 +211,16 @@ getJasmineRequireObj().Env = function(j$) {
 
     this.spyOn = function(obj, methodName) {
       if (j$.util.isUndefined(obj)) {
-        throw "spyOn could not find an object to spy upon for " + methodName + "()";
+        throw new Error("spyOn could not find an object to spy upon for " + methodName + "()");
       }
 
       if (j$.util.isUndefined(obj[methodName])) {
-        throw methodName + '() method does not exist';
+        throw new Error(methodName + '() method does not exist');
       }
 
       if (obj[methodName] && j$.isSpy(obj[methodName])) {
         //TODO?: should this return the current spy? Downside: may cause user confusion about spy state
-        throw methodName + ' has already been spied upon';
+        throw new Error(methodName + ' has already been spied upon');
       }
 
       var spy = j$.createSpy(methodName, obj[methodName]);

src/core/base.js

@@ -65,13 +65,17 @@ getJasmineRequireObj().base = function(j$) {
           return spyStrategy.exec.apply(this, arguments);
         };
 
-    spy.and = spyStrategy;
-    spy.calls = callTracker;
+    for (var prop in originalFn) {
+      if (prop === 'and' || prop === 'calls') {
+        throw new Error("Jasmine spies would overwrite the 'and' and 'calls' properties on the object being spied upon");
+      }
 
-    for (prop in originalFn) {
       spy[prop] = originalFn[prop];
     }
 
+    spy.and = spyStrategy;
+    spy.calls = callTracker;
+
     return spy;
   };