feat: throw error if the read-only property is tried to change (#749)

Author: 38elements

Diff for: docs/api/wrapper-array/README.md

@@ -4,13 +4,13 @@ A `WrapperArray` is an object that contains an array of [`Wrappers`](../wrapper/
 
 ## Properties
 
-### `wrappers` 
+### `wrappers`
 
-`array`: the `Wrappers` contained in the `WrapperArray`  
+`array` (read-only): the `Wrappers` contained in the `WrapperArray`
 
-### `length` 
+### `length`
 
-`number`: the number of `Wrappers` contained in the `WrapperArray`
+`number` (read-only): the number of `Wrappers` contained in the `WrapperArray`
 
 ## Methods
 

Diff for: docs/api/wrapper/README.md

@@ -14,13 +14,13 @@ A `Wrapper` is an object that contains a mounted component or vnode and methods
 
 `HTMLElement` (read-only): the root DOM node of the wrapper
 
-### `options` 
+### `options`
 
 #### `options.attachedToDocument`
 
 `Boolean` (read-only): True if `attachedToDocument` in mounting options was `true`
 
-#### `options.sync` 
+#### `options.sync`
 
 `Boolean` (read-only): True if `sync` in mounting options was not `false`
 

Diff for: packages/test-utils/src/vue-wrapper.js

@@ -1,6 +1,7 @@
 // @flow
 
 import Wrapper from './wrapper'
+import { throwError } from 'shared/util'
 import { setWatchersToSync } from './set-watchers-to-sync'
 import { orderWatchers } from './order-watchers'
 
@@ -11,17 +12,17 @@ export default class VueWrapper extends Wrapper implements BaseWrapper {
     // $FlowIgnore : issue with defineProperty
     Object.defineProperty(this, 'vnode', {
       get: () => vm._vnode,
-      set: () => {}
+      set: () => throwError('wrapper.vnode is read-only')
     })
     // $FlowIgnore
     Object.defineProperty(this, 'element', {
       get: () => vm.$el,
-      set: () => {}
+      set: () => throwError('wrapper.element is read-only')
     })
     // $FlowIgnore
     Object.defineProperty(this, 'vm', {
       get: () => vm,
-      set: () => {}
+      set: () => throwError('wrapper.vm is read-only')
     })
     if (options.sync) {
       setWatchersToSync(vm)

Diff for: packages/test-utils/src/wrapper-array.js

@@ -5,12 +5,21 @@ import type VueWrapper from './vue-wrapper'
 import { throwError, warn } from 'shared/util'
 
 export default class WrapperArray implements BaseWrapper {
-  wrappers: Array<Wrapper | VueWrapper>;
-  length: number;
+  +wrappers: Array<Wrapper | VueWrapper>;
+  +length: number;
 
   constructor (wrappers: Array<Wrapper | VueWrapper>) {
-    this.wrappers = wrappers || []
-    this.length = this.wrappers.length
+    const length = wrappers.length
+    // $FlowIgnore
+    Object.defineProperty(this, 'wrappers', {
+      get: () => wrappers,
+      set: () => throwError('wrapperArray.wrappers is read-only')
+    })
+    // $FlowIgnore
+    Object.defineProperty(this, 'length', {
+      get: () => length,
+      set: () => throwError('wrapperArray.length is read-only')
+    })
   }
 
   at (index: number): Wrapper | VueWrapper {

Diff for: packages/test-utils/src/wrapper.js

@@ -42,24 +42,24 @@ export default class Wrapper implements BaseWrapper {
       // $FlowIgnore
       Object.defineProperty(this, 'vnode', {
         get: () => vnode,
-        set: () => {}
+        set: () => throwError('wrapper.vnode is read-only')
       })
       // $FlowIgnore
       Object.defineProperty(this, 'element', {
         get: () => element,
-        set: () => {}
+        set: () => throwError('wrapper.element is read-only')
       })
       // $FlowIgnore
       Object.defineProperty(this, 'vm', {
         get: () => undefined,
-        set: () => {}
+        set: () => throwError('wrapper.vm is read-only')
       })
     }
     const frozenOptions = Object.freeze(options)
     // $FlowIgnore
     Object.defineProperty(this, 'options', {
       get: () => frozenOptions,
-      set: () => {}
+      set: () => throwError('wrapper.options is read-only')
     })
     if (
       this.vnode &&
@@ -399,7 +399,6 @@ export default class Wrapper implements BaseWrapper {
     }
 
     return !!(
-      this.element &&
       this.element.getAttribute &&
       this.element.matches(selector)
     )
@@ -667,7 +666,6 @@ export default class Wrapper implements BaseWrapper {
     })
 
     // $FlowIgnore : Problem with possibly null this.vm
-    this.vnode = this.vm._vnode
     orderWatchers(this.vm || this.vnode.context.$root)
     Vue.config.silent = originalConfig
   }
@@ -814,7 +812,7 @@ export default class Wrapper implements BaseWrapper {
    */
   destroy () {
     if (!this.isVueInstance()) {
-      throwError(`wrapper.destroy() can only be called on a Vue ` + `instance`)
+      throwError(`wrapper.destroy() can only be called on a Vue instance`)
     }
 
     if (this.element.parentNode) {

Diff for: test/specs/vuewrapper.js renamed to test/specs/vue-wrapper.spec.js

@@ -5,9 +5,10 @@ describeWithShallowAndMount('VueWrapper', mountingMethod => {
     it(`has the ${property} property which is read-only`, () => {
       const wrapper = mountingMethod({ template: '<div><p></p></div>' })
       expect(wrapper.constructor.name).to.equal('VueWrapper')
-      const originalProperty = wrapper[property]
-      wrapper[property] = 'foo'
-      expect(wrapper[property]).to.equal(originalProperty)
+      const message = `[vue-test-utils]: wrapper.${property} is read-only`
+      expect(() => { wrapper[property] = 'foo' })
+        .to.throw()
+        .with.property('message', message)
     })
   })
 })

Diff for: test/specs/wrapper-array.spec.js

@@ -7,13 +7,19 @@ describeWithShallowAndMount('WrapperArray', mountingMethod => {
     const wrapper = mountingMethod(compiled)
     const wrapperArray = wrapper.findAll('p')
     expect(wrapperArray.constructor.name).to.equal('WrapperArray')
-    if (wrappers) {
-      wrapperArray.wrappers = wrappers
-      wrapperArray.length = wrappers.length
-    }
-    return wrapperArray
+    return wrappers ? new wrapperArray.constructor(wrappers) : wrapperArray
   }
 
+  ['wrappers', 'length'].forEach(property => {
+    it(`has the ${property} property which is read-only`, () => {
+      const wrapperArray = getWrapperArray()
+      const message = `[vue-test-utils]: wrapperArray.${property} is read-only`
+      expect(() => { wrapperArray[property] = 'foo' })
+        .to.throw()
+        .with.property('message', message)
+    })
+  })
+
   it('returns class with length equal to length of wrappers passed in constructor', () => {
     const wrapperArray = getWrapperArray()
     expect(wrapperArray.length).to.equal(3)
@@ -67,8 +73,7 @@ describeWithShallowAndMount('WrapperArray', mountingMethod => {
       if (method === 'at') {
         return
       }
-      const wrapperArray = getWrapperArray()
-      wrapperArray.wrappers = []
+      const wrapperArray = getWrapperArray([])
       const message = `[vue-test-utils]: ${method} cannot be called on 0 items`
       expect(() => wrapperArray[method]())
         .to.throw()
@@ -99,8 +104,7 @@ describeWithShallowAndMount('WrapperArray', mountingMethod => {
       ) {
         return
       }
-      const wrapperArray = getWrapperArray()
-      wrapperArray.wrappers = [1, 2, 3]
+      const wrapperArray = getWrapperArray([1, 2, 3])
       const message = `[vue-test-utils]: ${method} must be called on a single wrapper, use at(i) to access a wrapper`
       expect(() => wrapperArray[method]())
         .to.throw()

Diff for: test/specs/wrapper.spec.js

@@ -6,9 +6,10 @@ describeWithShallowAndMount('Wrapper', mountingMethod => {
       const wrapper = mountingMethod({ template: '<div><p></p></div>' })
         .find('p')
       expect(wrapper.constructor.name).to.equal('Wrapper')
-      const originalProperty = wrapper[property]
-      wrapper[property] = 'foo'
-      expect(wrapper[property]).to.equal(originalProperty)
+      const message = `[vue-test-utils]: wrapper.${property} is read-only`
+      expect(() => { wrapper[property] = 'foo' })
+        .to.throw()
+        .with.property('message', message)
     })
   })
 })

Diff for: test/specs/wrapper/attributes.spec.js

@@ -15,11 +15,4 @@ describeWithShallowAndMount('attributes', mountingMethod => {
     const wrapper = mountingMethod(compiled)
     expect(wrapper.attributes()).to.eql({})
   })
-
-  it('returns empty object if wrapper element is null', () => {
-    const compiled = compileToFunctions('<div />')
-    const wrapper = mountingMethod(compiled)
-    wrapper.element = null
-    expect(wrapper.attributes()).to.eql({})
-  })
 })

Diff for: test/specs/wrapper/is.spec.js

@@ -28,12 +28,6 @@ describeWithShallowAndMount('is', mountingMethod => {
     expect(wrapper.is('#div')).to.equal(true)
   })
 
-  it('returns false if wrapper does not contain element', () => {
-    const wrapper = mountingMethod(ComponentWithChild)
-    wrapper.element = null
-    expect(wrapper.is('a')).to.equal(false)
-  })
-
   it('returns true if root node matches Vue Component selector', () => {
     const wrapper = mountingMethod(ComponentWithChild)
     const component = wrapper.findAll(Component).at(0)