feat: bundler (esbuild, nextjs) integration tests

[gabrielmfern]

This adds in a new directory integrations with a test file integrations.spec.ts that runs over the two integrations integrations/nextjs and integrations/esbuild respectively to make sure we don't introduce regressions that cause #625 or #587 respectively.

To actually get this to work reliably, I had to make sure that @react-email/render was not accessible for esbuild or turbopack builds. To do that, because of standard module resolution traversing parent node_modules directories, the test moves the integration's directory into the developer's tmp directory.

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Summary by cubic

Adds integration tests for Next.js (Turbopack) and esbuild to prevent bundler regressions when using the SDK. Tests build minimal apps in an isolated temp directory to avoid parent node_modules leaking (e.g., @react-email/render).

• New Features
  • Added integrations folder with minimal Next.js app and esbuild project using Resend.
  • Vitest builds each app from a tmp copy; package.json is rewritten to depend on the local SDK path.
  • New scripts: test:integrations and integration:nextjs; tsconfig now includes integrations.

To securely create a temporary directory, use a well-established library like tmp, which ensures random directory names, exclusive creation, and appropriate permissions.
Steps:

• Import tmp in the test file.
• Instead of path.resolve(os.tmpdir(), ...), call tmp.dirSync() (or its async equivalent), which returns a unique, safely created temp directory path.
• Remove the current logic for custom temp dir paths and creation checks—let tmp handle creation and permissions.
• Use that directory as the base for all test operations (copying, modifying the package).

Required changes:

• Add import tmp from 'tmp'; near the top.
• In prepareTemporaryIntegrationCopy, replace the explicit construction of temporaryIntegrationPath, its manual deletion, and the explicit mkdir with a single tmp.dirSync() call.
• Update all subsequent operations that use temporaryIntegrationPath as needed.

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[cubic-dev-ai]

2 issues found across 12 files

Prompt for AI agents (all 2 issues)

Understand the root cause of the following 2 issues and fix them.


<file name="integrations/integrations.spec.ts">

<violation number="1" location="integrations/integrations.spec.ts:73">
The esbuild integration test throws an error saying &quot;next.js build failed&quot;, so an esbuild failure would surface with the wrong integration name, making it harder to triage.</violation>
</file>

<file name="integrations/nextjs/app/route.js">

<violation number="1" location="integrations/nextjs/app/route.js:3">
Rule violated: **Initialisms and Acronyms Naming Conventions**

Rename the `GET` handler to use camelCase/PascalCase to comply with the initialism casing convention.</violation>
</file>

_{React with 👍 or 👎 to teach cubic. Mention @cubic-dev-ai to give feedback, ask questions, or re-run the review.}

[cubic-dev-ai]

The esbuild integration test throws an error saying "next.js build failed", so an esbuild failure would surface with the wrong integration name, making it harder to triage.

Prompt for AI agents

Address the following comment on integrations/integrations.spec.ts at line 73:

<comment>The esbuild integration test throws an error saying &quot;next.js build failed&quot;, so an esbuild failure would surface with the wrong integration name, making it harder to triage.</comment>

<file context>
@@ -0,0 +1,93 @@
+      },
+    );
+    if (buildInstall.status !== 0) {
+      throw new Error(&#39;next.js build failed&#39;);
+    }
+  });
</file context>

Suggested change

	throw new Error('next.js build failed');
	throw new Error('esbuild build failed');

[cubic-dev-ai]

Rule violated: Initialisms and Acronyms Naming Conventions

Rename the GET handler to use camelCase/PascalCase to comply with the initialism casing convention.

Prompt for AI agents

Address the following comment on integrations/nextjs/app/route.js at line 3:

<comment>Rename the `GET` handler to use camelCase/PascalCase to comply with the initialism casing convention.</comment>

<file context>
@@ -0,0 +1,7 @@
+import { Resend } from &#39;resend&#39;;
+
+export function GET() {
+  new Resend(&#39;&#39;);
+
</file context>