cleaning app opt at the beginning

lib/commands/session.js

@@ -20,6 +20,12 @@ commands.createSession = async function (caps) {
   // merge caps onto opts so we don't need to worry about what's where
   Object.assign(this.opts, this.caps);
 
+
+  // Prevents empty string caps so we don't need to test it everywhere
+  if (typeof this.opts.app === 'string' && this.opts.app.trim() === '') {
+    this.opts.app = null;
+  }
+
   if (!_.isUndefined(this.caps.newCommandTimeout)) {
     this.newCommandTimeoutMs = (this.caps.newCommandTimeout * 1000);
   }

lib/helpers.js

@@ -12,9 +12,11 @@ import request from 'request';
 const ZIP_EXTS = ['.zip', '.ipa'];
 
 async function configureApp (app, appExt) {
+  if (_.isNull(app) || _.isUndefined(app)) { return; }
+
   let newApp = null;
   let shouldUnzipApp = _.contains(ZIP_EXTS, path.extname(app));
-  if (app.substring(0, 4).toLowerCase() === "http") {
+  if ((app || '').substring(0, 4).toLowerCase() === "http") {
     logger.info(`Using downloadable app ${app}`);
     newApp = await downloadApp(app, shouldUnzipApp ? ".zip" : appExt);
     logger.info(`Downloaded app to ${newApp}`);