test(web): add chat-stream helper, thread fixture, and smoke spec

surfsense_web/tests/helpers/api/chat.ts

@@ -0,0 +1,67 @@
+import type { APIRequestContext } from "@playwright/test";
+import { authHeaders, BACKEND_URL } from "./auth";
+
+export type ChatStreamEvent = {
+	type: string;
+	payload: unknown;
+};
+
+export type ChatStreamResult = {
+	assistantText: string;
+	events: ChatStreamEvent[];
+};
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+	return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+export async function streamChatToCompletion(
+	request: APIRequestContext,
+	token: string,
+	args: { searchSpaceId: number; threadId: number; query: string }
+): Promise<ChatStreamResult> {
+	const response = await request.post(`${BACKEND_URL}/api/v1/new_chat`, {
+		headers: authHeaders(token),
+		data: {
+			chat_id: args.threadId,
+			search_space_id: args.searchSpaceId,
+			user_query: args.query,
+		},
+	});
+	if (!response.ok()) {
+		throw new Error(
+			`streamChatToCompletion failed (${response.status()}): ${await response.text()}`
+		);
+	}
+
+	const body = await response.text();
+	let assistantText = "";
+	let sawDone = false;
+	const events: ChatStreamEvent[] = [];
+
+	for (const rawFrame of body.split("\n\n")) {
+		const frame = rawFrame.trim();
+		if (!frame) continue;
+		if (!frame.startsWith("data: ")) continue;
+
+		const payloadText = frame.slice("data: ".length);
+		if (payloadText === "[DONE]") {
+			sawDone = true;
+			events.push({ type: "done", payload: "[DONE]" });
+			break;
+		}
+
+		const payload = JSON.parse(payloadText) as unknown;
+		const type = isRecord(payload) && typeof payload.type === "string" ? payload.type : "unknown";
+		if (type === "text-delta" && isRecord(payload) && typeof payload.delta === "string") {
+			assistantText += payload.delta;
+		}
+		events.push({ type, payload });
+	}
+
+	if (!sawDone) {
+		throw new Error(`Chat stream did not finish with [DONE]. Body: ${body.slice(0, 500)}`);
+	}
+
+	return { assistantText, events };
+}