Problem: lack of code coverage for gravity module

[thomas-nguy]

Current unit test coverage reports :

ok  	github.com/peggyjv/gravity-bridge/module/v2/app	3.369s	coverage: 1.3% of statements
?   	github.com/peggyjv/gravity-bridge/module/v2/app/params	[no test files]
ok  	github.com/peggyjv/gravity-bridge/module/v2/app/upgrades/v2	1.961s	coverage: 51.7% of statements
?   	github.com/peggyjv/gravity-bridge/module/v2/cmd/gravity	[no test files]
ok  	github.com/peggyjv/gravity-bridge/module/v2/cmd/gravity/cmd	2.941s	coverage: 1.2% of statements
ok  	github.com/peggyjv/gravity-bridge/module/v2/x/gravity	2.533s	coverage: 65.2% of statements
?   	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/client	[no test files]
ok  	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/client/cli	0.885s	coverage: 1.1% of statements
ok  	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/keeper	2.162s	coverage: 58.4% of statements
ok  	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/migrations/v1	1.197s	coverage: 94.9% of statements
?   	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/migrations/v1/keeper	[no test files]
?   	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/migrations/v1/types	[no test files]
ok  	github.com/peggyjv/gravity-bridge/module/v2/x/gravity/types	3.341s	coverage: 2.0% of statements

target 70% for keeper