Instead of calling setup() and teardown() before and after running all tests, call it for every test case so that all test are independent from other tests
Remove the unnecessary test case struct when there is only one test case
Use %v instead of %q in test failure messages so they're easier to read
Split the CreateSpan error cases into two separate tests
Clean up the mock trace tests
setup()andteardown()before and after running all tests, call it for every test case so that all test are independent from other tests%vinstead of%qin test failure messages so they're easier to readCreateSpanerror cases into two separate tests