Add better onboard testing (#4007)

src/lib/statsig/statsig.tsx

@@ -130,6 +130,28 @@ export function useGate(): (gateName: Gate) => boolean {
   return gate
 }
 
+/**
+ * Debugging tool to override a gate. USE ONLY IN E2E TESTS!
+ */
+export function useDangerousSetGate(): (
+  gateName: Gate,
+  value: boolean,
+) => void {
+  const cache = React.useContext(GateCache)
+  if (!cache) {
+    throw Error(
+      'useDangerousSetGate() cannot be called outside StatsigProvider.',
+    )
+  }
+  const dangerousSetGate = React.useCallback(
+    (gateName: Gate, value: boolean) => {
+      cache.set(gateName, value)
+    },
+    [cache],
+  )
+  return dangerousSetGate
+}
+
 function toStatsigUser(did: string | undefined): StatsigUser {
   let userID: string | undefined
   if (did) {