unit test coverage is always 0% , even log shows that Linter:UnitTest over

[JeffreyDing11223]

unit test coverage is always 0% , even the log shows that "Linter:UnitTest over".

command:
goreporter -p ./ -r /Users/jeffrey -f html
log:

2018/11/11 19:33:45 The template path is not specified,and will use the default template
2018/11/11 19:33:45 There are no packages that are excepted, review all items of the package
2018/11/11 19:33:45 Linter:CountCode over,time consuming 0.251907667s
2018/11/11 19:33:45 Linter:Cyclo over,time consuming 0.297925743s
2018/11/11 19:33:45 Linter:Deadcode over,time consuming 0.298405016s
2018/11/11 19:33:50 Linter:DependGraph over,time consuming 5.698402892s
2018/11/11 19:33:50 Linter:Depth over,time consuming 5.742482226s
2018/11/11 19:33:51 Linter:ImportPackages over,time consuming 6.782828042s
2018/11/11 19:34:01 Linter:Interfacer over,time consuming 16.57413304s
2018/11/11 19:34:01 Linter:Simple over,time consuming 16.803392849s
2018/11/11 19:34:02 Linter:SpellCheck over,time consuming 16.910021184s
2018/11/11 19:34:11 Linter:UnitTest over,time consuming 26.280821136s
2018/11/11 19:34:13 Linter:GoLint over,time consuming 27.898436823s
2018/11/11 19:34:21 Linter:GoVet over,time consuming 36.791485132s
2018/11/11 19:34:29 Linter:GoFmt over,time consuming 43.893475809s
2018/11/11 19:34:29
2018/11/11 19:34:29
2018/11/11 19:34:29
2018/11/11 19:34:29
2018/11/11 19:34:29
2018/11/11 19:34:29 To display report file:///Users/jeffrey/core-2018-11-11-19-34-29.html in browser
2018/11/11 19:34:29 GoReporter Finished,time consuming 44.41447197s