codesandbox CI is failing but not reproducible locally

[eps1lon]

Example: https://ci.codesandbox.io/status/testing-library/react-testing-library/pr/1020/builds/223848

This build was triggered by testing-library/react-testing-library#1020.

However, when I run git clean -fdx; yarn; yarn run build locally I do not get any failure even with the exact node version.

The error in codesandbox CI looks like the install isn't complete or using older packages. Each install should do a complete fresh install since we're not using any lockfile.

[eps1lon]

Fixed by forcing CI to use npm instead of yarn:

diff --git a/.codesandbox/ci.json b/.codesandbox/ci.json
index f866879..bf3237b 100644
--- a/.codesandbox/ci.json
+++ b/.codesandbox/ci.json
@@ -1,4 +1,5 @@
 {
+  "installCommand": "install:csb",
   "sandboxes": ["new", "github/kentcdodds/react-testing-library-examples"],
   "node": "12"
 }
diff --git a/package.json b/package.json
index cbf6136..55b31ec 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,7 @@
     "build:bundle:pure": "dotenv -e .bundle.main.env -e .bundle.pure.env kcd-scripts build -- --bundle --no-clean",
     "build:main": "kcd-scripts build --no-clean",
     "format": "kcd-scripts format",
+    "install:csb": "npm install",
     "lint": "kcd-scripts lint",
     "setup": "npm install && npm run validate -s",
     "test": "kcd-scripts test",