Add testhelper that can create single widgets

[worldpotato]

To test a single widget. How to use? look here: https://github.com/RedTo/MyApp-Example

[coveralls]

Pull Request Test Coverage Report for Build 149

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 98.734%

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Totals
Change from base Build 145:	0.0%
Covered Lines:	78
Relevant Lines:	79

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💛 - Coveralls