add WithStyle test util

Signed-off-by: balanza <[email protected]>

assets/js/lib/test-utils/ui/index.jsx

@@ -0,0 +1,27 @@
+import React from 'react';
+
+const css = require('fs').readFileSync(
+  `${__dirname}/../../../../../priv/static/assets/app.css`,
+  'utf8'
+);
+
+/**
+ * Prepend the application global css in a <style> element.
+ * It's meant to be used in component testing when css classes must be resolved.
+ *
+ * @example
+ *
+ * render(
+ *   <WithStyle>
+ *     <Elem />
+ *   </WithStyle>
+ * );
+ */
+export function WithStyle({ children }) {
+  return (
+    <>
+      <style>{css}</style>
+      {children}
+    </>
+  );
+}

assets/package.json

@@ -87,6 +87,7 @@
     "lint": "eslint . --ext js,jsx",
     "format:check": "prettier -c .",
     "format": "prettier --write .",
+    "pretest": "ls ../priv/static/assets/app.css || npm run tailwind:build",
     "test": "jest",
     "chromatic": "npx chromatic --exit-zero-on-changes"
   }