diff --git a/.gitignore b/.gitignore
index 580167b6..2ff9c850 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,4 @@ node_modules/
 public/
 searchIndex.js
 package-lock.json
+tmp
diff --git a/.npmignore b/.npmignore
index df87f670..391a2cba 100644
--- a/.npmignore
+++ b/.npmignore
@@ -13,3 +13,4 @@ pages/
 script/
 # we ignore this because everything in src/ is copied out in script/prepublish
 src/
+tmp/
diff --git a/package.json b/package.json
index 212e2d8d..e282d6fa 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
     "dev": "cd docs && npm install && npm run develop",
     "start-storybook": "start-storybook -p 8001",
     "build-storybook": "build-storybook -o .storybuild",
-    "pretest": "yarn dist && npm i --no-save @primer/css",
+    "pretest": "yarn dist && script/pretest",
     "test": "jest",
     "test-deprecations": "script/test-deprecations.js",
     "release": "changeset publish"
diff --git a/script/pretest b/script/pretest
new file mode 100755
index 00000000..b5c5953c
--- /dev/null
+++ b/script/pretest
@@ -0,0 +1,7 @@
+#!/bin/bash
+set -e
+
+mkdir -p tmp
+cd tmp
+echo "{\"package\":\"tmp\",\"version\":\"0.0.0\"}" > package.json
+yarn add @primer/css