fix(test): stop re-running prototype augment in spec tests. (#6105)

Co-authored-by: John Jenkins <john.jenkins@nanoporetech.com>

Author: johnjenkins

src/runtime/proxy-component.ts

@@ -29,6 +29,14 @@ export const proxyComponent = (
 ): d.ComponentConstructor => {
   const prototype = (Cstr as any).prototype;
 
+  if (BUILD.isTesting) {
+    if (prototype.done) {
+      // @ts-expect-error - we don't want to re-augment the prototype. This happens during spec tests.
+      return;
+    }
+    prototype.done = true;
+  }
+
   /**
    * proxy form associated custom element lifecycle callbacks
    * @ref https://web.dev/articles/more-capable-form-controls#lifecycle_callbacks
@@ -113,9 +121,9 @@ export const proxyComponent = (
                 // the element is not constructing
                 (ref && ref.$flags$ & HOST_FLAGS.isConstructingInstance) === 0 &&
                 // the member is a prop
-                (cmpMeta.$members$[memberName][0] & MEMBER_FLAGS.Prop) !== 0 &&
+                (memberFlags & MEMBER_FLAGS.Prop) !== 0 &&
                 // the member is not mutable
-                (cmpMeta.$members$[memberName][0] & MEMBER_FLAGS.Mutable) === 0
+                (memberFlags & MEMBER_FLAGS.Mutable) === 0
               ) {
                 consoleDevWarn(
                   `@Prop() "${memberName}" on <${cmpMeta.$tagName$}> is immutable but was modified from within the component.\nMore information: https://stenciljs.com/docs/properties#prop-mutability`,

src/runtime/test/prop-warnings.spec.tsx

@@ -1,6 +1,18 @@
 import { Component, h, Method, Prop } from '@stencil/core';
 import { newSpecPage } from '@stencil/core/testing';
 
+@Component({
+  tag: 'shared-cmp',
+  shadow: true,
+})
+class SharedCmp {
+  @Prop() a = 'Boom!';
+
+  render() {
+    return `${this.a}`;
+  }
+}
+
 describe('prop', () => {
   const spy = jest.spyOn(console, 'warn').mockImplementation();
 
@@ -89,4 +101,28 @@ describe('prop', () => {
     expect(root).toEqualHtml('<cmp-a>2</cmp-a>');
     expect(spy).not.toHaveBeenCalled();
   });
+
+  it('should not show warning when component is used across multiple tests - first time', async () => {
+    const { root, waitForChanges } = await newSpecPage({
+      components: [SharedCmp],
+      html: `<shared-cmp></shared-cmp>`,
+    });
+
+    root.a = 'Bam!';
+    await waitForChanges();
+
+    expect(spy).not.toHaveBeenCalled();
+  });
+
+  it('should not show warning when component is used across multiple tests - second time', async () => {
+    const { root, waitForChanges } = await newSpecPage({
+      components: [SharedCmp],
+      html: `<shared-cmp></shared-cmp>`,
+    });
+
+    root.a = 'Boom!';
+    await waitForChanges();
+
+    expect(spy).not.toHaveBeenCalled();
+  });
 });