test(ssr): add test for dynamic imports (#4878)

Co-authored-by: Will Harney <[email protected]>

packages/@lwc/engine-server/src/__tests__/fixtures.spec.ts

@@ -57,6 +57,10 @@ async function compileFixture({
         plugins: [
             lwcRollupPlugin({
                 enableDynamicComponents: true,
+                experimentalDynamicComponent: {
+                    loader: path.join(__dirname, './utils/custom-loader.js'),
+                    strictSpecifier: false,
+                },
                 modules: [
                     {
                         dir: modulesDir,

packages/@lwc/engine-server/src/__tests__/fixtures/dynamic-imports/basic/expected.html

@@ -0,0 +1,5 @@
+<x-dynamic-component>
+  <template shadowrootmode="open">
+    Importee: 
+  </template>
+</x-dynamic-component>

packages/@lwc/engine-server/src/__tests__/fixtures/dynamic-imports/basic/index.js

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

packages/@lwc/engine-server/src/__tests__/fixtures/dynamic-imports/basic/modules/x/dynamic/dynamic.html

@@ -0,0 +1,3 @@
+<template>
+    Importee: {importee}
+</template>

packages/@lwc/engine-server/src/__tests__/fixtures/dynamic-imports/basic/modules/x/dynamic/dynamic.js

@@ -0,0 +1,12 @@
+import { LightningElement } from 'lwc';
+
+export default class DynamicCtor extends LightningElement {
+    importee
+
+    constructor() {
+        super()
+        import('x/fake').then(result => {
+            this.importee = result
+        })
+    }
+}

packages/@lwc/engine-server/src/__tests__/fixtures/dynamic-imports/basic/modules/x/fake/fake.js

@@ -0,0 +1 @@
+export default "do not actually import me"

packages/@lwc/engine-server/src/__tests__/utils/custom-loader.js

@@ -0,0 +1,3 @@
+export function load() {
+    return Promise.resolve('stub');
+}

packages/@lwc/ssr-compiler/src/__tests__/utils/expected-failures.ts

@@ -30,6 +30,7 @@ export const expectedFailures = new Set([
     'comments-text-preserve-off/index.js',
     'dynamic-components/slots/shadow/index.js',
     'dynamic-components/slots/light/index.js',
+    'dynamic-imports/basic/index.js',
     'dynamic-slots/index.js',
     'empty-text-with-comments-non-static-optimized/index.js',
     'if-conditional-slot-content/index.js',