define func newApp() for internal testability

[Songmu]

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[coveralls]

Pull Request Test Coverage Report for Build 6747241185

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• 5 of 17 (29.41%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 28.035%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
config.go	0	1	0.0%
main.go	0	11	0.0%

Totals
Change from base Build 6747124863:	0.1%
Covered Lines:	254
Relevant Lines:	906

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💛 - Coveralls