adding tests for good measure

spec/emitters/custom-event-emitter.js

+if(typeof require === 'function') {
+  const buster             = require("buster")
+      , CustomEventEmitter = require("../../lib/emitters/custom-event-emitter")
+      , Helpers            = require('../buster-helpers')
+      , dialect            = Helpers.getTestDialect()
+}
+
+buster.spec.expose()
+buster.testRunner.timeout = 1000
+
+describe(Helpers.getTestDialectTeaser("CustomEventEmitter"), function() {
+	describe("proxy", function () {
+		/* Tests could _probably_ be run synchronously, but for future proofing we're basing it on the events */
+
+		it("should correctly work with success listeners", function (done) {
+			var emitter = new CustomEventEmitter()
+				, proxy = new CustomEventEmitter()
+				, success = this.spy()
+
+			emitter.success(success)
+			proxy.success(function () {
+				process.nextTick(function () {
+					expect(success.called).toEqual(true)
+					done();
+				})
+			})
+
+			proxy.proxy(emitter)
+			proxy.emit('success')
+		})
+
+		it("should correctly work with error listeners", function (done) {
+			var emitter = new CustomEventEmitter()
+				, proxy = new CustomEventEmitter()
+				, error = this.spy()
+
+			emitter.error(error)
+			proxy.error(function () {
+				process.nextTick(function () {
+					expect(error.called).toEqual(true)
+					done();
+				})
+			})
+
+			proxy.proxy(emitter)
+			proxy.emit('error')
+		})
+
+		it("should correctly work with complete/done listeners", function (done) {
+			var emitter = new CustomEventEmitter()
+				, proxy = new CustomEventEmitter()
+				, complete = this.spy()
+
+			emitter.complete(complete)
+			proxy.complete(function () {
+				process.nextTick(function () {
+					expect(complete.called).toEqual(true)
+					done();
+				})
+			})
+
+			proxy.proxy(emitter)
+			proxy.emit('success')
+		})
+	});
+});
\ No newline at end of file