No amp4test log on travis. (#19611)

* No amp4test log on travis.

* read --files to enable logging

* Update js doc

* clean up

* print error in correct format

* also do --verbose

* use --verbose

* Update js doc

build-system/amp4test.js

@@ -16,17 +16,20 @@
 'use strict';
 
 const app = module.exports = require('express').Router();
+const minimist = require('minimist');
+const argv = minimist(
+    process.argv.slice(2), {boolean: ['strictBabelTransform']});
+
 
 /* eslint-disable max-len */
 
 /**
- * Logs the given messages to the console in local dev mode, but not while
- * running automated tests.
+ * Logs the given messages to the console when --verbose is specified.
  * @param {*} messages
  */
 function log(...messages) {
-  if (!process.env.AMP_TEST) {
-    console.log(messages);
+  if (argv.verbose) {
+    console.log.apply(console, messages);
   }
 }
 

build-system/tasks/runtime-test.js

@@ -544,8 +544,6 @@ async function runTests() {
     };
   }
 
-  // Run fake-server to test XHR responses.
-  process.env.AMP_TEST = 'true';
   const server = gulp.src(process.cwd(), {base: '.'}).pipe(webserver({
     port: 8081,
     host: 'localhost',