datastore: use new rpcreplay method

Use the new Replayer.Connection method to establish a fake
connection on replay.

Change-Id: I5327100a932327584531b20f9dc9217883a27b39
Reviewed-on: https://code-review.googlesource.com/c/37152
Reviewed-by: kokoro <[email protected]>
Reviewed-by: Eno Compton <[email protected]>

datastore/integration_test.go

@@ -21,7 +21,6 @@ import (
 	"flag"
 	"fmt"
 	"log"
-	"net"
 	"os"
 	"reflect"
 	"sort"
@@ -119,7 +118,7 @@ func initReplay() {
 	}
 	timeNow = ri.Time.In(time.Local)
 
-	conn, err := replayConn(rep)
+	conn, err := rep.Connection()
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -133,27 +132,6 @@ func initReplay() {
 	log.Printf("replaying from %s", replayFilename)
 }
 
-func replayConn(rep *rpcreplay.Replayer) (*grpc.ClientConn, error) {
-	// If we make a real connection we need creds from somewhere, and they
-	// might not be available, for instance on Travis.
-	// Replaying doesn't require a connection live at all, but we need
-	// something to attach gRPC interceptors to.
-	// So we start a local listener and connect to it, then close them down.
-	// TODO(jba): build something like this into the replayer?
-	l, err := net.Listen("tcp", "127.0.0.1:0")
-	if err != nil {
-		return nil, err
-	}
-	conn, err := grpc.Dial(l.Addr().String(),
-		append([]grpc.DialOption{grpc.WithInsecure()}, rep.DialOptions()...)...)
-	if err != nil {
-		return nil, err
-	}
-	conn.Close()
-	l.Close()
-	return conn, nil
-}
-
 func newClient(ctx context.Context, t *testing.T, dialOpts []grpc.DialOption) *Client {
 	if testing.Short() {
 		t.Skip("Integration tests skipped in short mode")