fix(trigger('focus')) added natural to jsdom behavior (#1777)

* Fix for trigger('focus')

Added test case and the fix for wrapper trigger

* Extended types notation and jsdoc

* Added type check and fallback for focus processing

Author: Th3Un1q3

packages/test-utils/src/wrapper.js

@@ -829,6 +829,33 @@ export default class Wrapper implements BaseWrapper {
     return this.element.textContent.trim()
   }
 
+  /**
+   * Simulates event triggering
+   */
+  __simulateTrigger(type: string, options?: Object): void {
+    const regularEventTrigger = (type, options) => {
+      const event = createDOMEvent(type, options)
+      return this.element.dispatchEvent(event)
+    }
+
+    const focusEventTrigger = (type, options) => {
+      if (this.element instanceof HTMLElement) {
+        return this.element.focus()
+      }
+
+      regularEventTrigger(type, options)
+    }
+
+    const triggerProcedureMap = {
+      focus: focusEventTrigger,
+      __default: regularEventTrigger
+    }
+
+    const triggerFn = triggerProcedureMap[type] || triggerProcedureMap.__default
+
+    return triggerFn(type, options)
+  }
+
   /**
    * Dispatches a DOM event on wrapper
    */
@@ -869,8 +896,7 @@ export default class Wrapper implements BaseWrapper {
       return nextTick()
     }
 
-    const event = createDOMEvent(type, options)
-    this.element.dispatchEvent(event)
+    this.__simulateTrigger(type, options)
     return nextTick()
   }
 }

test/resources/components/component-with-multiple-inputs.vue

@@ -0,0 +1,57 @@
+<template>
+  <div>
+    <input
+      v-for="index of 5"
+      @focus="onFocus(index)"
+      :id="index"
+      :data-test-position="index"
+      :ref="refNameByIndex(index)"
+      :key="index"
+      type="text"
+    />
+  </div>
+</template>
+
+<script>
+export default {
+  name: 'component-with-multiple-inputs',
+  data: () => ({ activeInputIndex: null }),
+  computed: {
+    inputRefAtIndex() {
+      return index => this.$refs[this.refNameByIndex(index)]
+    }
+  },
+
+  methods: {
+    refNameByIndex(index) {
+      return `input${index}`
+    },
+
+    returnToLastSelectedInput() {
+      return this.focusInput(this.inputRefAtIndex(this.activeInputIndex))
+    },
+
+    onFocus(index) {
+      const isOdd = Boolean(index % 2)
+      if (isOdd) {
+        return this.returnToLastSelectedInput()
+      }
+      this.activeInputIndex = index
+    },
+
+    focusInput(inputRef) {
+      if (!inputRef) {
+        return
+      }
+      const [input] = inputRef
+      input.focus()
+    }
+  },
+
+  mounted() {
+    this.focusInput(this.focusInput(this.inputRefAtIndex(2)))
+  }
+}
+</script>
+
+<style scoped></style>

test/specs/wrapper-array/trigger.spec.js

@@ -1,7 +1,11 @@
 import { compileToFunctions } from 'vue-template-compiler'
 import ComponentWithEvents from '~resources/components/component-with-events.vue'
+import ComponentWithMultipleInputs from '~resources/components/component-with-multiple-inputs.vue'
 import { describeWithShallowAndMount } from '~resources/utils'
 
+const assertElementIsFocused = element =>
+  expect(document.activeElement.id).toEqual(element.id)
+
 describeWithShallowAndMount('trigger', mountingMethod => {
   it('causes click handler to fire when wrapper.trigger("click") is called on a Component', async () => {
     const clickHandler = jest.fn()
@@ -34,6 +38,26 @@ describeWithShallowAndMount('trigger', mountingMethod => {
     expect(keydownHandler).toHaveBeenCalled()
   })
 
+  it('should really focus element when trigger focus was called', async () => {
+    const wrapper = mountingMethod(ComponentWithMultipleInputs, {
+      attachTo: document.body
+    })
+
+    assertElementIsFocused(wrapper.get('[data-test-position="2"]').element)
+
+    await wrapper.get('[data-test-position="4"]').trigger('focus')
+
+    assertElementIsFocused(wrapper.get('[data-test-position="4"]').element)
+
+    await wrapper.get('[data-test-position="3"]').trigger('focus')
+
+    assertElementIsFocused(wrapper.get('[data-test-position="4"]').element)
+
+    await wrapper.get('[data-test-position="2"]').trigger('focus')
+
+    assertElementIsFocused(wrapper.get('[data-test-position="2"]').element)
+  })
+
   it('throws an error if type is not a string', () => {
     const wrapper = mountingMethod(ComponentWithEvents)
     const invalidSelectors = [