Honor reset without the app capability

Fixes appium#157

Author: tiagoshibata

lib/driver.js

@@ -171,7 +171,7 @@ class AndroidDriver extends BaseDriver {
     // unlock the device
     await helpers.unlock(this.adb);
     // If the user sets autoLaunch to false, they are responsible for initAUT() and startAUT()
-    if (!this.appOnDevice && this.opts.autoLaunch) {
+    if (this.opts.autoLaunch) {
       // set up app under test
       await this.initAUT();
     }
@@ -225,14 +225,20 @@ class AndroidDriver extends BaseDriver {
     let launchInfo = await helpers.getLaunchInfo(this.adb, this.opts);
     Object.assign(this.opts, launchInfo);
     Object.assign(this.caps, launchInfo);
-    if (!this.opts.skipUninstall) {
-      await this.adb.uninstallApk(this.opts.appPackage);
-    }
     // install app
     if (!this.opts.app) {
+      if (this.opts.fullReset) {
+        log.errorAndThrow('Full reset requires an app capability, use fastReset if app is not provided');
+      }
       log.debug('No app capability. Assuming it is already on the device');
+      if (this.opts.fastReset) {
+        await helpers.resetApp(this.adb, this.opts.app, this.opts.appPackage, this.opts.fastReset);
+      }
       return;
     }
+    if (!this.opts.skipUninstall) {
+      await this.adb.uninstallApk(this.opts.appPackage);
+    }
     await helpers.installApkRemotely(this.adb, this.opts.app, this.opts.appPackage, this.opts.fastReset);
     this.apkStrings[this.opts.language] = await helpers.pushStrings(
         this.opts.language, this.adb, this.opts);