去测试总是通过为什么?

I installed go and tried the first part on How to write go code

And after a while of not seeing the desired result I notice go test always passes, always!

What am I missing?

$ go version
go version go1
$ mkdir -p src/example/math 

$ cat >src/example/math/sum_test.go <<.
> package math
>
> import "testing"
>
> func SumTest( t *testing.T ) {
>    t.Errorf("ssss %d", 1 )
> }
> .

$ go test example/math
ok      example/math    0.044s

I'm using windows x64 and I'm using git-bash as shell

From the go command man page:

A test function is one named TestXXX (where XXX is any alphanumeric string not starting with a lower case letter) and should have the signature,

func TestXXX(t *testing.T) { ... }

Your SumTest() function doesn't follow that pattern, and is likely to be ignored.
This should work better:

func TestSum( t *testing.T )