tightened some rpcErr loose ends and revised some tests

call.go

@@ -137,15 +137,15 @@ func Invoke(ctx context.Context, method string, args, reply proto.Message, cc *C
 		)
 		// TODO(zhaoq): Need a formal spec of retry strategy for non-failfast rpcs.
 		if lastErr != nil && c.failFast {
-			return lastErr
+			return toRPCErr(lastErr)
 		}
 		t, ts, err = cc.wait(ctx, ts)
 		if err != nil {
 			if lastErr != nil {
 				// This was a retry; return the error from the last attempt.
-				return lastErr
+				return toRPCErr(lastErr)
 			}
-			return err
+			return Errorf(codes.Internal, "%v", err)
 		}
 		stream, err = sendRPC(ctx, callHdr, t, args, topts)
 		if err != nil {

test/end2end_test.go

@@ -233,8 +233,24 @@ func TestReconnectTimeout(t *testing.T) {
 		t.Fatalf("Failed to dial to the server %q: %v", addr, err)
 	}
 	lis.Close()
-	// Sleep till reconnect times out.
-	time.Sleep(2 * timeOut)
+	tc := testpb.NewTestServiceClient(conn)
+	waitC := make(chan struct{})
+	go func() {
+		defer close(waitC)
+		argSize := 271828
+		respSize := 314159
+		req := &testpb.SimpleRequest{
+			ResponseType: testpb.PayloadType_COMPRESSABLE.Enum(),
+			ResponseSize: proto.Int32(int32(respSize)),
+			Payload:      newPayload(testpb.PayloadType_COMPRESSABLE, int32(argSize)),
+		}
+		_, err := tc.UnaryCall(context.Background(), req)
+		if err != grpc.Errorf(codes.Internal, "%v", grpc.ErrClientConnClosing) {
+			t.Fatalf("TestService/UnaryCall(_, _) = _, %v, want _, %v", err, grpc.Errorf(codes.Internal, "%v", grpc.ErrClientConnClosing))
+		}
+	}()
+	// Block untill reconnect times out.
+	<-waitC
 	if err := conn.Close(); err != grpc.ErrClientConnClosing {
 		t.Fatalf("%v.Close() = %v, want %v", conn, err, grpc.ErrClientConnClosing)
 	}