test: Add testutil.HttpServer

The goal is to remove supertest as it does not support typescript well
and there's really no good reason for the dependency. Also no websocket
testing support.

test/testutil.ts

@@ -0,0 +1,65 @@
+import * as http from "http"
+import { logger } from "@coder/logger"
+import { ensureAddress } from "../src/node/app"
+import * as nodeFetch from "node-fetch"
+
+export class HttpServer {
+  private hs = http.createServer()
+
+  /**
+   * listen starts the server on a random localhost port.
+   * Use close to cleanup when done.
+   */
+  public listen(fn: http.RequestListener): Promise<void> {
+    this.hs.on("request", fn)
+
+    let resolved = false
+    return new Promise((res, rej) => {
+      this.hs.listen(0, "localhost", () => {
+        res()
+        resolved = true
+      })
+
+      this.hs.on("error", (err) => {
+        if (!resolved) {
+          rej(err)
+        } else {
+          // Promise resolved earlier so this is some other error.
+          logError("server error", err)
+        }
+      })
+    })
+  }
+
+  /**
+   * close cleans up the server.
+   */
+  public close(): Promise<void> {
+    return new Promise((res, rej) => {
+      this.hs.close((err) => {
+        if (err) {
+          rej(err)
+          return
+        }
+        res()
+      })
+    })
+  }
+
+  /**
+   * fetch fetches the request path.
+   * The request path must be rooted!
+   */
+  public fetch(requestPath: string, opts?: nodeFetch.RequestInit): Promise<nodeFetch.Response> {
+    return nodeFetch.default(`${ensureAddress(this.hs)}${requestPath}`, opts)
+  }
+}
+
+
+export function logError(prefix: string, err: any): void {
+  if (err instanceof Error) {
+    logger.error(`${prefix}: ${err.message} ${err.stack}`)
+  } else {
+    logger.error(`${prefix}: ${err}`)
+  }
+}