pi/packages/coding-agent/test/input-transform-streaming-example.test.ts

import { describe, expect, it, vi } from "vitest";
import inputTransformStreaming from "../examples/extensions/input-transform-streaming.ts";
import type {
	ExecResult,
	ExtensionAPI,
	ExtensionContext,
	InputEvent,
	InputEventResult,
} from "../src/core/extensions/index.ts";

type InputHandler = (event: InputEvent, ctx: ExtensionContext) => Promise<InputEventResult | undefined>;

function setup(execResult: ExecResult) {
	let handler: InputHandler | undefined;

	const exec = vi.fn<ExtensionAPI["exec"]>().mockResolvedValue(execResult);

	const api = {
		on: (event: string, h: InputHandler) => {
			if (event === "input") handler = h;
		},
		exec,
	} as unknown as ExtensionAPI;

	inputTransformStreaming(api);

	const ctx = {} as ExtensionContext;

	function emit(text: string, streamingBehavior?: "steer" | "followUp") {
		return handler!({ type: "input", text, source: "interactive", streamingBehavior }, ctx);
	}

	return { emit, exec };
}

describe("input-transform-streaming example", () => {
	const diffOutput = " src/index.ts | 5 ++---\n 1 file changed, 2 insertions(+), 3 deletions(-)";
	const gitSuccess: ExecResult = { stdout: diffOutput, stderr: "", code: 0, killed: false };
	const gitEmpty: ExecResult = { stdout: "", stderr: "", code: 0, killed: false };
	const gitFail: ExecResult = { stdout: "", stderr: "not a git repo", code: 128, killed: false };

	it("skips exec during steering", async () => {
		const { emit, exec } = setup(gitSuccess);
		const result = await emit("what changes did I make?", "steer");
		expect(result).toEqual({ action: "continue" });
		expect(exec).not.toHaveBeenCalled();
	});

	it("transforms when idle and text matches trigger", async () => {
		const { emit, exec } = setup(gitSuccess);
		const result = await emit("review my changes");
		expect(exec).toHaveBeenCalledWith("git", ["diff", "--stat"]);
		expect(result).toMatchObject({ action: "transform" });
		const text = (result as { text: string }).text;
		expect(text).toContain("review my changes");
		expect(text).toContain("src/index.ts");
	});

	it("transforms when queued as follow-up", async () => {
		const { emit, exec } = setup(gitSuccess);
		const result = await emit("show me the diff", "followUp");
		expect(exec).toHaveBeenCalled();
		expect(result).toMatchObject({ action: "transform" });
	});

	it("continues when text does not match trigger", async () => {
		const { emit, exec } = setup(gitSuccess);
		const result = await emit("explain this function");
		expect(result).toEqual({ action: "continue" });
		expect(exec).not.toHaveBeenCalled();
	});

	it("continues when git diff is empty", async () => {
		const { emit } = setup(gitEmpty);
		const result = await emit("any changes?");
		expect(result).toEqual({ action: "continue" });
	});

	it("continues when git fails", async () => {
		const { emit } = setup(gitFail);
		const result = await emit("show modified files");
		expect(result).toEqual({ action: "continue" });
	});
});