more tests for middleware runner

Author: SkippyZA

src/utils/compose-middleware.js

@@ -2,12 +2,12 @@ const isFunction = fn => typeof fn === 'function'
 
 export default function composeMiddleware (middleware) {
   if (!Array.isArray(middleware)) {
-    throw new TypeError('Middleware stack must be an array!')
+    throw new TypeError('Stack must be an array')
   }
 
   for (const fn of middleware) {
     if (!isFunction(fn)) {
-      throw new TypeError('Middleware must be composed of functions!')
+      throw new TypeError('Middleware must be composed of functions')
     }
   }
 

test/unit/utils/compose-middleware.spec.js

@@ -1,14 +1,24 @@
+import { expect } from 'chai'
 import composeMiddleware from '../../../src/utils/compose-middleware'
 
 describe('compose middleware', () => {
   describe('with no middleware', () => {
-    it('should resolve an empty promise', () => {
+    it('should fail if a non-array supplied', () => {
+      expect(() => composeMiddleware(null)).to.throw(TypeError, 'Stack must be an array')
+    })
+
+    it('should fail if the array contains non-function values', () => {
+      const middleware = [ 'hello', 'world' ]
+      expect(() => composeMiddleware(middleware)).to.throw(TypeError, 'Middleware must be composed of functions')
+    })
+
+    it('should resolve an empty promise when supplied an empty array', () => {
       return composeMiddleware([])()
     })
   })
 
   describe('with multiple middleware applied', () => {
-    it('should workd', () => {
+    it('execute them with the supplied parameters', () => {
       let executionCount = 0
 
       const middlewareA = (req, res, done) => {