test: add repro for vuejs#1973

tests/components/DefinePropsAndDefineEmits.vue

@@ -0,0 +1,15 @@
+<template>
+  <div :class="placement">
+    <slot />
+  </div>
+</template>
+
+<script lang="ts" setup>
+defineProps<{
+  placement: 'start' | 'end' | 'top' | 'bottom';
+}>();
+
+defineEmits<{
+  (e: 'update', value: string): void;
+}>();
+</script>

tests/mount.spec.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it, vi } from 'vitest'
 import { defineComponent } from 'vue'
 import { mount } from '../src'
+import DefinePropsAndDefineEmits from './components/DefinePropsAndDefineEmits.vue'
 import HelloFromVitestPlayground from './components/HelloFromVitestPlayground.vue'
 
 describe('mount: general tests', () => {
@@ -32,4 +33,15 @@ describe('mount: general tests', () => {
 
     expect(spy).not.toHaveBeenCalled()
   })
+
+  it('should mount a component with props, emits and slot (#1973)', () => {
+    const wrapper = mount(DefinePropsAndDefineEmits, {
+      props: {
+        placement: 'end'
+      },
+      slots: { default: 'Hello' }
+    })
+    expect(wrapper.get('div').text()).toContain('Hello')
+    expect(wrapper.get('div').classes()).toContain('end')
+  })
 })