Are there tests validating cross-client compatibility?

[carlosrymer]

I'm curious to know if these exists and can be provided upfront?

[kopax]

Yes me too. I have been trying with your tool and the first mail I have sent to my self arrive on my phone.

We could see a small line with the background color but no content, while on thunderbird it look normal.

I am looking also for a way to quickly test the rendering in most used email client. Also, how can we troubleshoot?