kubernetes/staging/src/k8s.io/apiserver/pkg/storage/etcd3/testserver/test_server.go

// getAvailablePort returns a TCP port that is available for binding.
func getAvailablePorts(count int) ([]int, error) { … }

// NewTestConfig returns a configuration for an embedded etcd server.
// The configuration is based on embed.NewConfig(), with the following adjustments:
//   - sets UnsafeNoFsync = true to improve test performance (only reasonable in a test-only
//     single-member server we never intend to restart or keep data from)
//   - uses free ports for client and peer listeners
//   - cleans up the data directory on test termination
//   - silences server logs other than errors
func NewTestConfig(t testing.TB) *embed.Config { … }

// RunEtcd starts an embedded etcd server with the provided config
// (or NewTestConfig(t) if nil), and returns a client connected to the server.
// The server is terminated when the test ends.
func RunEtcd(t testing.TB, cfg *embed.Config) *kubernetes.Client { … }