test(ssr): assert read-only-props for lwc:is (#4919)

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/dynamic-child/expected.html

@@ -0,0 +1,15 @@
+<x-parent>
+  <template shadowrootmode="open">
+    <x-child>
+      <template shadowrootmode="open">
+        <div>
+
+array: error hit during mutation
+object: error hit during mutation
+deep: error hit during mutation
+object: error hit during deletion
+        </div>
+      </template>
+    </x-child>
+  </template>
+</x-parent>

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/dynamic-child/modules/x/child/child.js

@@ -0,0 +1,39 @@
+import { LightningElement, api } from "lwc";
+
+export default class extends LightningElement {
+  @api array
+  @api object
+  @api deep
+
+  result
+
+  connectedCallback() {
+    const results = []
+
+    try {
+      this.array.push('bar')
+    } catch (err) {
+      results.push('array: error hit during mutation')
+    }
+
+    try {
+      this.object.foo = 'baz'
+    } catch (err) {
+      results.push('object: error hit during mutation')
+    }
+
+    try {
+      this.deep.foo[0].quux = 'quux'
+    } catch (err) {
+      results.push('deep: error hit during mutation')
+    }
+
+    try {
+      delete this.object.foo
+    } catch (err) {
+      results.push('object: error hit during deletion')
+    }
+
+    this.result = '\n' + results.join('\n')
+  }
+}

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/dynamic-child/modules/x/parent/parent.html

@@ -0,0 +1,8 @@
+<template>
+  <lwc:component lwc:is={ctor}
+    array={array}
+    object={object}
+    deep={deep}
+  >
+  </lwc:component>
+</template>

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/dynamic-child/modules/x/parent/parent.js

@@ -0,0 +1,9 @@
+import { LightningElement } from "lwc";
+import Child from 'x/child'
+
+export default class extends LightningElement {
+  ctor = Child
+  array = [1, 2, 3]
+  object = { foo: 'bar '}
+  deep = { foo: [{ bar: 'baz' }]}
+}

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/pseudo-attribute/index.js

@@ -0,0 +1,3 @@
+export const tagName = 'x-parent';
+export { default } from 'x/parent';
+export * from 'x/parent';

packages/@lwc/engine-server/src/__tests__/fixtures/read-only-props/pseudo-attribute/modules/x/child/child.html

@@ -0,0 +1,3 @@
+<template>
+  <div>{result}</div>
+</template>