refactor: compose browser application runtimes

test/browser-apps/helpers/cli-fixture.ts

@@ -0,0 +1,172 @@
+import { resolve } from "@std/path";
+
+const repositoryRoot = resolve(import.meta.dirname!, "../../..");
+const cliDirectory = resolve(repositoryRoot, "src/apps/cli");
+const cliDist = resolve(cliDirectory, "dist/index.cjs");
+
+export interface CliResult {
+    readonly code: number;
+    readonly combined: string;
+    readonly stderr: string;
+    readonly stdout: string;
+}
+
+export class TemporaryDirectory implements AsyncDisposable {
+    private constructor(readonly path: string) {}
+
+    static async create(prefix: string): Promise<TemporaryDirectory> {
+        return new TemporaryDirectory(await Deno.makeTempDir({ prefix: `${prefix}.` }));
+    }
+
+    resolve(...parts: string[]): string {
+        return resolve(this.path, ...parts);
+    }
+
+    async [Symbol.asyncDispose](): Promise<void> {
+        await Deno.remove(this.path, { recursive: true }).catch(() => {});
+    }
+}
+
+async function collectStream(stream: ReadableStream<Uint8Array>, append: (text: string) => void): Promise<void> {
+    const reader = stream.getReader();
+    const decoder = new TextDecoder();
+    try {
+        while (true) {
+            const { done, value } = await reader.read();
+            if (done) {
+                append(decoder.decode());
+                return;
+            }
+            if (value !== undefined) {
+                append(decoder.decode(value, { stream: true }));
+            }
+        }
+    } finally {
+        reader.releaseLock();
+    }
+}
+
+export async function runCli(...args: string[]): Promise<CliResult> {
+    const output = await new Deno.Command("node", {
+        args: [cliDist, ...args],
+        cwd: cliDirectory,
+        stdin: "null",
+        stdout: "piped",
+        stderr: "piped",
+    }).output();
+    const decoder = new TextDecoder();
+    const stdout = decoder.decode(output.stdout);
+    const stderr = decoder.decode(output.stderr);
+    return {
+        code: output.code,
+        combined: stdout + stderr,
+        stderr,
+        stdout,
+    };
+}
+
+export async function initSettingsFile(path: string): Promise<void> {
+    const result = await runCli("init-settings", "--force", path);
+    if (result.code !== 0) {
+        throw new Error(`CLI settings initialisation failed with code ${result.code}\n${result.combined}`);
+    }
+}
+
+export function sanitiseCatStdout(raw: string): string {
+    return raw
+        .split("\n")
+        .filter((line) => line !== "[CLIWatchAdapter] File watching is not enabled in CLI version")
+        .join("\n");
+}
+
+export class BackgroundCliProcess {
+    #stdout = "";
+    #stderr = "";
+    readonly #stdoutDone: Promise<void>;
+    readonly #stderrDone: Promise<void>;
+
+    constructor(readonly child: Deno.ChildProcess) {
+        this.#stdoutDone = collectStream(child.stdout, (text) => {
+            this.#stdout += text;
+        });
+        this.#stderrDone = collectStream(child.stderr, (text) => {
+            this.#stderr += text;
+        });
+    }
+
+    get combined(): string {
+        return this.#stdout + this.#stderr;
+    }
+
+    async stop(): Promise<number> {
+        try {
+            this.child.kill("SIGTERM");
+        } catch {
+            // The process has already exited.
+        }
+        const status = await this.child.status;
+        await Promise.all([this.#stdoutDone, this.#stderrDone]);
+        return status.code;
+    }
+}
+
+export function startCliInBackground(...args: string[]): BackgroundCliProcess {
+    return new BackgroundCliProcess(
+        new Deno.Command("node", {
+            args: [cliDist, ...args],
+            cwd: cliDirectory,
+            stdin: "null",
+            stdout: "piped",
+            stderr: "piped",
+        }).spawn()
+    );
+}
+
+type WaitForPortOptions = {
+    timeoutMs?: number;
+    intervalMs?: number;
+    connectTimeoutMs?: number;
+};
+
+async function connectWithTimeout(hostname: string, port: number, timeoutMs: number): Promise<void> {
+    let timeout: ReturnType<typeof setTimeout> | undefined;
+    try {
+        const connection = await Promise.race([
+            Deno.connect({ hostname, port }),
+            new Promise<never>((_, reject) => {
+                timeout = setTimeout(() => reject(new Error(`Connection timed out after ${timeoutMs} ms`)), timeoutMs);
+            }),
+        ]);
+        connection.close();
+    } finally {
+        if (timeout !== undefined) {
+            clearTimeout(timeout);
+        }
+    }
+}
+
+export async function waitForPort(
+    hostname: string,
+    port: number,
+    options: WaitForPortOptions = {}
+): Promise<void> {
+    const timeoutMs = options.timeoutMs ?? 15_000;
+    const intervalMs = options.intervalMs ?? 250;
+    const connectTimeoutMs = options.connectTimeoutMs ?? 1_000;
+    const started = Date.now();
+    let lastError: unknown;
+
+    while (Date.now() - started < timeoutMs) {
+        try {
+            await connectWithTimeout(hostname, port, connectTimeoutMs);
+            return;
+        } catch (error) {
+            lastError = error;
+            await new Promise((resolvePromise) => setTimeout(resolvePromise, intervalMs));
+        }
+    }
+    throw new Error(
+        `Port ${hostname}:${port} did not become ready within ${timeoutMs} ms` +
+            (lastError === undefined ? "" : ` (last error: ${String(lastError)})`)
+    );
+}