fix: check for element in hasAttribute

Author: eddyerburgh

src/wrappers/wrapper.js

@@ -217,7 +217,10 @@ export default class Wrapper implements BaseWrapper {
       }
       return vmCtorMatchesName(this.vm, selector.name)
     }
-    return this.element.getAttribute && this.element.matches(selector)
+
+    return !!(this.element &&
+    this.element.getAttribute &&
+    this.element.matches(selector))
   }
 
   /**

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

@@ -22,6 +22,12 @@ describe('is', () => {
     expect(wrapper.is('#div')).to.equal(true)
   })
 
+  it('returns false if wrapper does not contain element', () => {
+    const wrapper = mount(ComponentWithChild)
+    wrapper.element = null
+    expect(wrapper.is('a')).to.equal(false)
+  })
+
   it('returns true if root node matches Vue Component selector', () => {
     const wrapper = mount(ComponentWithChild)
     const component = wrapper.findAll(Component).at(0)