fix: check for element in trigger

Author: eddyerburgh

src/wrappers/wrapper.js

@@ -327,6 +327,10 @@ export default class Wrapper implements BaseWrapper {
       throwError('wrapper.trigger() must be passed a string')
     }
 
+    if (!this.element) {
+      throwError('cannot call wrapper.trigger() on a wrapper without an element')
+    }
+
     const modifiers = {
       enter: 13,
       tab: 9,

test/unit/specs/mount/Wrapper/text.spec.js

@@ -10,7 +10,7 @@ describe('text', () => {
     expect(wrapper.text()).to.equal(text)
   })
 
-  it('throws error if wrapper does not contain eleemnt', () => {
+  it('throws error if wrapper does not contain elememnt', () => {
     const compiled = compileToFunctions(`<div />`)
     const wrapper = mount(compiled)
     wrapper.element = null

test/unit/specs/mount/Wrapper/trigger.spec.js

@@ -74,6 +74,14 @@ describe('trigger', () => {
     expect(info.calledWith(true)).to.equal(true)
   })
 
+  it('throws error if wrapper does not contain eleemnt', () => {
+    const wrapper = mount({ render: () => {} })
+    wrapper.element = null
+    const fn = () => wrapper.trigger('click')
+    const message = '[vue-test-utils]: cannot call wrapper.trigger() on a wrapper without an element'
+    expect(fn).to.throw().with.property('message', message)
+  })
+
   it('throws an error if type is not a string', () => {
     const wrapper = mount(ComponentWithEvents)
     const invalidSelectors = [