Fix inflexible/slightly broken m.request tests

test/mithril.mount.js

@@ -648,7 +648,7 @@ describe("m.mount()", function () {
 	})
 
 	function resolveXhr() {
-		mock.XMLHttpRequest.$instances.pop().onreadystatechange()
+		mock.XMLHttpRequest.$instances.pop().$resolve().onreadystatechange()
 		mock.requestAnimationFrame.$resolve()
 	}
 

test/mithril.request.js

@@ -4,6 +4,7 @@ describe("m.request()", function () {
 	// Much easier to read
 	function resolve() {
 		var xhr = mock.XMLHttpRequest.$instances.pop()
+		xhr.$resolve.apply(xhr, arguments)
 		xhr.onreadystatechange()
 		return xhr
 	}
@@ -381,4 +382,21 @@ describe("m.request()", function () {
 		// For good measure
 		mock.requestAnimationFrame.$resolve()
 	})
+
+	it("can use a config correctly", function () {
+		var config = sinon.spy()
+		var result = m.prop()
+		var error = sinon.spy
+		var opts = {
+			method: "GET",
+			url: "/test",
+			config: config
+		}
+		m.request(opts).then(result, error)
+		var xhr = resolve({foo: "bar"})
+
+		expect(config).to.be.calledWithExactly(xhr, opts)
+		expect(result()).to.eql({foo: "bar"})
+		expect(error).to.not.be.called
+	})
 })