Database schema version of 1.4.0 cannot be upgraded

Hi, guys, I tried to clone the source of mattermost and run ‘make test’. At first, I got the error message"no such id: mattermost-openldap". After I comment mattermost-openldap part in the makefile, I got the following messages:
go test -run=. -test.v -test.timeout=650s -covermode=count -coverprofile=capi.out ./api || exit 1 === RUN TestGetLogs [2016/08/24 16:32:27 CST] [INFO] Loaded system translations for 'en' from '/Users/guo/mygo/src/github.com/mattermost/platform/i18n/en.json' [2016/08/24 16:32:34 CST] [CRIT] The database schema version of 1.4.0 cannot be upgraded. You must not skip a version. --- FAIL: TestGetLogs (8.38s) panic: The database schema version of 1.4.0 cannot be upgraded. You must not skip a version. [recovered] panic: The database schema version of 1.4.0 cannot be upgraded. You must not skip a version.
How do I solve it?
Many thanks.

I use go1.6.2 and mac os x 10.10.5

Please follow the upgrade guide documentation.