fixed broken tests

src/lib/index.js

@@ -50,10 +50,10 @@ FetchMock.sandbox = function() {
 	// this construct allows us to create a fetch-mock instance which is also
 	// a callable function, while circumventing circularity when defining the
 	// object that this function should be bound to
-	const proxy = (url, options) => sandbox.fetchHandler(url, options);
+	const fetchMockProxy = (url, options) => sandbox.fetchHandler(url, options);
 
 	const sandbox = Object.assign(
-		proxy, // Ensures that the entire returned object is a callable function
+		fetchMockProxy, // Ensures that the entire returned object is a callable function
 		FetchMock, // prototype methods
 		this.createInstance(), // instance data
 		{

test/specs/sandbox.test.js

@@ -154,9 +154,11 @@ module.exports = (fetchMock, theGlobal) => {
 				Response
 			} = fetchMock.sandbox();
 
-			expect(fetch.name).to.equal('proxy');
+			expect(fetch.name).to.equal('fetchMockProxy');
 			expect(new Headers()).to.be.an.instanceOf(fetchMock.config.Headers);
-			expect(new Request()).to.be.an.instanceOf(fetchMock.config.Request);
+			expect(new Request('http://example.com')).to.be.an.instanceOf(
+				fetchMock.config.Request
+			);
 			expect(new Response()).to.be.an.instanceOf(fetchMock.config.Response);
 		});
 	});