title: Use "go test" to list all tests case
body: <p>With <code>go test -v pattern</code> I can select and only run the tests that matches a pattern, but is there any way that I can list all test cases without run them. There is this case that the project just handed over to me has a lot of test case and I need to select some tests to run. I know greping the sources <code>xxx_test.go</code> is a way but is there more elegant way? I mean, each test has its meta data stored in some where, right? as the tests are required to be in a specific signature(<code>func TestXXX(*testing.T)</code>). This meta data can be used to do this kind of work.</p>