test(app): deflake slash terminal toggle flow (#17881)

packages/app/src/testing/prompt.ts

@@ -0,0 +1,56 @@
+import type { E2EWindow } from "./terminal"
+
+export type PromptProbeState = {
+  popover: "at" | "slash" | null
+  slash: {
+    active: string | null
+    ids: string[]
+  }
+  selected: string | null
+  selects: number
+}
+
+export const promptEnabled = () => {
+  if (typeof window === "undefined") return false
+  return (window as E2EWindow).__opencode_e2e?.prompt?.enabled === true
+}
+
+const root = () => {
+  if (!promptEnabled()) return
+  return (window as E2EWindow).__opencode_e2e?.prompt
+}
+
+export const promptProbe = {
+  set(input: Omit<PromptProbeState, "selected" | "selects">) {
+    const state = root()
+    if (!state) return
+    state.current = {
+      popover: input.popover,
+      slash: {
+        active: input.slash.active,
+        ids: [...input.slash.ids],
+      },
+      selected: state.current?.selected ?? null,
+      selects: state.current?.selects ?? 0,
+    }
+  },
+  select(id: string) {
+    const state = root()
+    if (!state) return
+    const prev = state.current
+    state.current = {
+      popover: prev?.popover ?? null,
+      slash: {
+        active: prev?.slash.active ?? null,
+        ids: [...(prev?.slash.ids ?? [])],
+      },
+      selected: id,
+      selects: (prev?.selects ?? 0) + 1,
+    }
+  },
+  clear() {
+    const state = root()
+    if (!state) return
+    state.current = undefined
+  },
+}