add mock refactor

[coveralls]

Pull Request Test Coverage Report for Build 645141876

• 71 of 104 (68.27%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-7.0%) to 79.675%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lightning_mocker.go	14	16	87.5%
btcd.go	17	21	80.95%
lnd.go	40	67	59.7%
<!--	Total:	71	104	68.27%	-->

Totals
Change from base Build 643772224:	-7.0%
Covered Lines:	196
Relevant Lines:	246

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💛 - Coveralls