Fix terminal e2e flakiness with a real terminal driver (#17144)

packages/app/src/testing/terminal.ts

@@ -0,0 +1,64 @@
+export const terminalAttr = "data-pty-id"
+
+export type TerminalProbeState = {
+  connected: boolean
+  rendered: string
+  settled: number
+}
+
+export type E2EWindow = Window & {
+  __opencode_e2e?: {
+    terminal?: {
+      enabled?: boolean
+      terminals?: Record<string, TerminalProbeState>
+    }
+  }
+}
+
+const seed = (): TerminalProbeState => ({
+  connected: false,
+  rendered: "",
+  settled: 0,
+})
+
+const root = () => {
+  if (typeof window === "undefined") return
+  const state = (window as E2EWindow).__opencode_e2e?.terminal
+  if (!state?.enabled) return
+  state.terminals ??= {}
+  return state.terminals
+}
+
+export const terminalProbe = (id: string) => {
+  const set = (next: Partial<TerminalProbeState>) => {
+    const terms = root()
+    if (!terms) return
+    terms[id] = { ...(terms[id] ?? seed()), ...next }
+  }
+
+  return {
+    init() {
+      set(seed())
+    },
+    connect() {
+      set({ connected: true })
+    },
+    render(data: string) {
+      const terms = root()
+      if (!terms) return
+      const prev = terms[id] ?? seed()
+      terms[id] = { ...prev, rendered: prev.rendered + data }
+    },
+    settle() {
+      const terms = root()
+      if (!terms) return
+      const prev = terms[id] ?? seed()
+      terms[id] = { ...prev, settled: prev.settled + 1 }
+    },
+    drop() {
+      const terms = root()
+      if (!terms) return
+      delete terms[id]
+    },
+  }
+}