[test] add more flags to execute unit test by go test

[allencloud]

Ⅰ. Issue Description

I think we should add more flags to pouch's unit test. Here is the test code

function unit-test()
{
    cd $BUILDPATH/src/github.com/alibaba/pouch
    go test -i
    for d in `go list ./... | grep -v 'github.com/alibaba/pouch/test' | grep -v 'github.com/alibaba/pouch/extra' | grep -v 'github.com/alibaba/pouch/vendor' `
    do
        go test -coverprofile=profile.out -covermode=atomic $d
        if [ -f profile.out ] ; then
            cat profile.out >> coverage.txt
            rm profile.out >/dev/null 2>&1
        fi
    done
}

In the code, we have found that we use go test -coverprofile=profile.out -covermode=atomic $d to make it.

While I am afraid more flags should be added into the go test, for example --race to detect code which may be potential race.

I think this will guarantee more about the quality of Pouch.

Ⅱ. Describe what happened

NO more test flag in unit test.

Ⅲ. Describe what you expected to happen

more test flag in unit test.

[allencloud]

Do we need to support more test flags here, and I think we already added --race. But I still think we need more input from Golang experts and test experts, like @fuweid @shaloulcy @Letty5411 @chuanchang @sunyuan3 😄