From 3cd66869a7d55ac2b59c285971bc0a3a9d2fecdb Mon Sep 17 00:00:00 2001
From: cexbrayat <cedric@ninja-squad.com>
Date: Tue, 26 Jan 2021 16:29:55 +0100
Subject: [PATCH 1/2] repro: spy on vm

---
 tests/vm.spec.ts | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tests/vm.spec.ts b/tests/vm.spec.ts
index 6f2a3b31d..136d74029 100644
--- a/tests/vm.spec.ts
+++ b/tests/vm.spec.ts
@@ -24,4 +24,25 @@ describe('vm', () => {
 
     expect(wrapper.vm.isEnabled).toBe(false)
   })
+
+  it('allows spying on vm', async () => {
+    const Component = defineComponent({
+      name: 'VTUComponent',
+      template: '<div @click="toggle()">{{ msg }}</div>',
+      setup() {
+        const msg = 'hello'
+        const isEnabled = ref(true)
+        const toggle = () => (isEnabled.value = !isEnabled.value)
+        return { msg, isEnabled, toggle }
+      }
+    })
+
+    const wrapper = mount(Component)
+
+    jest.spyOn(wrapper.vm, 'toggle')
+
+    await wrapper.get('div').trigger('click')
+
+    expect(wrapper.vm.toggle).toHaveBeenCalled()
+  })
 })

From d05502268d64c29befa532a82b63a942b5bcbbc6 Mon Sep 17 00:00:00 2001
From: cexbrayat <cedric@ninja-squad.com>
Date: Tue, 26 Jan 2021 18:01:07 +0100
Subject: [PATCH 2/2] fix: add hasOwnProperty to wrapper.vm

This allows Jest to spy on the proxied vm
Fixes #309
---
 src/mount.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/mount.ts b/src/mount.ts
index 13e7a756e..17ed85d20 100644
--- a/src/mount.ts
+++ b/src/mount.ts
@@ -441,8 +441,11 @@ export function mount(
   // if not, use the return value from app.mount.
   const appRef = vm.$refs[MOUNT_COMPONENT_REF] as ComponentPublicInstance
   const $vm = Reflect.ownKeys(appRef).length ? appRef : vm
+  // we add `hasOwnProperty` so jest can spy on the proxied vm without throwing
+  $vm.hasOwnProperty = (property) => {
+    return Reflect.has($vm, property)
+  }
   console.warn = warnSave
-
   return createWrapper(app, $vm, setProps)
 }