it("can overwrite config settings with default settings", function() {
   interface ITestSettings {
     obj: {
       obj: {
         str: string;
       };
       nr: number;
     };
     bool: boolean;
   }
   const defaults: DefaultSettings<ITestSettings> = {
     obj: ensure.object({
       obj: ensure.object({
         str: "Hallo world!"
       }),
       nr: 1
     }),
     bool: true
   };
   const settings = mergeDefaults({ obj: "Hallo universe!" }, defaults);
   expect(isObject(settings.obj)).to.be.true;
   expect(isObject(settings.obj.obj)).to.be.true;
   expect(settings.obj.obj.str).to.equal("Hallo world!");
   expect(settings.obj.nr).to.equal(1);
   expect(settings.bool).to.be.true;
 });

  function computeData(data) {
    if (data && util.isObject(data)) {
      if (data instanceof Error) {
        data = { message: data.message, error: data.stack };
      }
      if (typeof(data.toLogObj) === 'function') {
        return CircularJSON.stringify(snipsecret(data.toLogObj()));
      } else {
        return CircularJSON.stringify(snipsecret(data));
      }

    } else {
      return data;
    }
  }

/* istanbul ignore next: no crash reporters when testing */
function reportRollbar(ctx: Context, err: Error) {
	const request: any = {
		headers: ctx.request.headers,
		protocol: ctx.request.protocol,
		url: ctx.request.url,
		method: ctx.request.method,
		body: isObject(ctx.request.body) ? JSON.stringify(ctx.request.body) : ctx.request.body,
		user_ip: ctx.request.get('x-forwarded-for') || ctx.ip || '0.0.0.0',
	};
	if (ctx.state.user) {
		request.user = {
			id: ctx.state.user.id,
			email: ctx.state.user.email,
			username: ctx.state.user.name || ctx.state.user.username,
		};
	}
	rollbar.error(err, request, ctx.state.request);
}

function log(ctx: Context, start: number, len: number, err: any = null, event: string = null) {

	const statusCode = err
		? (err.statusCode || err.status || 500)
		: (ctx.status || 404);
	let length: string;
	if ([204, 205, 304].includes(statusCode)) {
		length = '';
	} else if (len == null) {
		length = '-';
	} else {
		length = bytes(len).toLowerCase();
	}
	let cache: string = '';
	if (ctx.response.headers['x-cache-api']) {
		cache = ' [' + ctx.response.headers['x-cache-api'].toLowerCase() + ']';
	}

	const ip = ctx.request.get('x-forwarded-for') || ctx.ip || '0.0.0.0';
	const user = ctx.state.user ? ctx.state.user.name || ctx.state.user.username : '';
	let logUserIp: string;
	if (user) {
		logUserIp = chalk.cyan(user) + ':' + chalk.blueBright(ip);
	} else {
		logUserIp = chalk.blueBright(ip);
	}

	const upstream = err ? chalk.redBright('*ERR* ') : event === 'close' ? chalk.yellowBright('*CLOSED* ') : '';

	const logStatus = statusStyle[Math.floor(statusCode / 100) * 100] || statusStyle[100];
	const logMethod = methodStyle[ctx.method] || methodStyle.GET;
	const duration = Date.now() - start;
	ctx.state.request.duration = duration;
	ctx.state.request.size = len;

	// log this
	const message = `[${logUserIp}] ${upstream}${logStatus(' ' + statusCode + ' ')} ${logMethod(ctx.method + ' ' + ctx.originalUrl)} ${duration}ms - ${length}${cache}`;
	const level = statusCode >= 500 ? 'error' : 'info';
	const fullLog = statusCode >= 400 && statusCode !== 404;
	const requestHeaders = stripAuthHeaders(ctx.request.headers);
	logger.text(ctx.state, level, message);
	logger.json(ctx.state, level, {
		type: 'access',
		message: `${ctx.method} ${ctx.originalUrl} [${ctx.response.status}]`,
		level,
		request: {
			id: ctx.state.request.id,
			ip: ctx.state.request.ip,
			method: ctx.request.method,
			path: ctx.request.url,
			headers: fullLog ? Object.keys(requestHeaders)
				.filter(header => !['accept', 'connection', 'pragma', 'cache-control', 'host', 'origin'].includes(header))
				.reduce((obj: { [key: string]: string }, key: string) => { obj[key] = requestHeaders[key]; return obj; }, {}) : undefined,
			body: ctx.request.get('content-type').startsWith('application/json') ? ctx.request.rawBody : undefined,
		},
		response: {
			status: ctx.response.status,
			body: fullLog && ctx.response.get('content-type').startsWith('application/json') ? (isObject(ctx.response.body) ? JSON.stringify(ctx.response.body) : ctx.response.body) : undefined,
			headers: fullLog ? Object.keys(ctx.response.headers)
				.filter(header => !['x-request-id', 'x-user-id', 'x-user-dirty', 'x-cache-api', 'x-response-time', 'x-token-refresh', 'vary', 'access-control-allow-origin', 'access-control-allow-credentials', 'access-control-expose-headers'].includes(header))
				.reduce((obj: { [key: string]: string }, key: string) => { obj[key] = ctx.response.headers[key]; return obj; }, {}) : undefined,
			duration: ctx.state.request.duration,
			size: ctx.state.request.size,
			cached: ctx.response.headers['x-cache-api'] ? ctx.response.headers['x-cache-api'] === 'HIT' : undefined,
		},
	});
}