Check the values of myKey and myRev first in Unlock method to prevent calling Unlock without Lock. Because this may cause the value of pfx to be deleted by mistake.
Signed-off-by: chenyahui <cyhone@qq.com>
The code now ensures that each of the test is running in its own directory as opposed to shared os.tempdir.
```
$ (cd tests && env go test -timeout=15m --race go.etcd.io/etcd/tests/v3/integration/clientv3/examples -run ExampleAuth)
2022/04/03 10:24:59 Running tests (examples): ...
2022/04/03 10:24:59 the function can be called only in the test context. Was integration.BeforeTest() called ?
2022/04/03 10:24:59 2022-04-03T10:24:59.462+0200 INFO m0 LISTEN GRPC {"member": "m0", "grpcAddr": "localhost:m0", "m.Name": "m0"}
```
% (cd tests && go vet ./...)
stderr: # go.etcd.io/etcd/tests/v3/integration/clientv3/concurrency_test
stderr: integration/clientv3/concurrency/election_test.go:74:6: call to (*T).Fatal from a non-test goroutine
stderr: integration/clientv3/concurrency/mutex_test.go:57:4: call to (*T).Fatal from a non-test goroutine
They used to take >10min with coverage, so were causing interrupted
Travis runs.
Know thay fit in 100-150s (together), thanks also to parallel
execution.
