Function makeTestRPCAndExpectItToReachBackend

balancer/rls/helpers_test.go:223–248

makeTestRPCAndExpectItToReachBackend is a test helper function which makes the EmptyCall RPC on the given ClientConn and verifies that it reaches a backend. The latter is accomplished by listening on the provided channel which gets pushed to whenever the backend in question gets an RPC. There are m

(ctx context.Context, t *testing.T, cc *grpc.ClientConn, ch chan struct{})

// Therefore, we do not return an error when the RPC fails. Instead, we wait for
// the context to expire before failing.
func makeTestRPCAndExpectItToReachBackend(ctx context.Context, t *testing.T, cc *grpc.ClientConn, ch chan struct{}) {
	t.Helper()

	// Drain the backend channel before performing the RPC to remove any
	// notifications from previous RPCs.
	select {
	case <-ch:
	default:
	}

	for {
		if err := ctx.Err(); err != nil {
			t.Fatalf("Timeout when waiting for RPCs to be routed to the given target: %v", err)
		}
		sCtx, sCancel := context.WithTimeout(ctx, defaultTestShortTimeout)
		client := testgrpc.NewTestServiceClient(cc)
		client.EmptyCall(sCtx, &testpb.Empty{})

		select {
		case <-sCtx.Done():
		case <-ch:
			sCancel()
			return
		}
	}
}

// makeTestRPCAndVerifyError is a test helper function which makes the EmptyCall
// RPC on the given ClientConn and verifies that the RPC fails with the given