I have successfully completed the trailhead challenge in my Dev org which is as follows:
Create a test harness app and component
Let's get set up for doing development right now. You'll create a test harness Lightning application, and add a simple component to it. Then you'll verify that you can see changes in the component.

• Create a new Lightning component named myFirstComponent
• Add this static text to the component: I solemnly swear I know JavaScript
• Create a new Lightning application named harnessApp
• Add myFirstComponent to the harness app with this markup: <c:myFirstComponent/>
• Click the Preview button and verify your text is displayed
• Make a change to the static text so it reads: I am proficient in JavaScript
• Click the Preview button again and verify your change is displayed

When I try to verify the challenge, it displays as error as follows:
Challenge Not yet complete... here's what's wrong: 
The 'harnessApp' Lightning App does not contain ''.

I am unable to understand the error. Anyone who received similar kind of error and were able to proceed further, Please help me with this.

Hi Team,

I am trying to check the challenge 'Learn the Process for Developing Lightning Components'', but getting error as below.

Error:
Challenge Not yet complete... here's what's wrong: 
The 'harnessApp' Lightning App does not contain ''.

App code :harnessApp
<aura:application>    
    <c:myFirstComponent/>    
</aura:application>

Component code: myFirstComponent
<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
    <p>I am proficient in JavaScript</p>
</aura:component>

Please hlep me to get is solved. I am unbale to understand what went wrong.

Thanks,
Ash G