test: add initial gRPC server test

Including a fixture to simplify upcoming gRPC server tests.

Also call shimGordianClient where it probably needed to be called,
although I did not manually test that it is working as intended.

gserver/internal/ggrpc/ggrpctest/fixture.go

@@ -0,0 +1,72 @@
+package ggrpctest
+
+import (
+	"context"
+	"net"
+	"testing"
+
+	"github.com/gordian-engine/gcosmos/gserver/internal/ggrpc"
+	"github.com/gordian-engine/gcosmos/internal/copy/gtest"
+	"github.com/gordian-engine/gordian/tm/tmstore/tmmemstore"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc"
+)
+
+// Fixture contains a gRPC server and client,
+// ready to use for testing the gRPC services.
+type Fixture struct {
+	Server *ggrpc.GordianGRPC
+	Client ggrpc.GordianGRPCClient
+
+	// TODO: either pull up the rest of the necessary fields from GRPCServerConfig
+	// or just outright expose GRPCServerConfig.
+	FinalizationStore *tmmemstore.FinalizationStore
+	MirrorStore       *tmmemstore.MirrorStore
+}
+
+// NewFixture returns a new fixture whose lifecycle is associated
+// with the given context.
+// It registers cleanup through t.Cleanup.
+// The caller must be sure to defer context cancellation
+// in order for the fixture to shut down properly.
+func NewFixture(t *testing.T, ctx context.Context) Fixture {
+	t.Helper()
+
+	log := gtest.NewLogger(t)
+
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = ln.Close()
+	})
+
+	fs := tmmemstore.NewFinalizationStore()
+	ms := tmmemstore.NewMirrorStore()
+
+	srv := ggrpc.NewGordianGRPCServer(
+		ctx,
+		log.With("sys", "server"),
+		ggrpc.GRPCServerConfig{
+			Listener: ln,
+
+			FinalizationStore: fs,
+			MirrorStore:       ms,
+		},
+	)
+	t.Cleanup(srv.Wait)
+
+	gc, err := grpc.NewClient(
+		ln.Addr().String(),
+		grpc.WithInsecure(),
+	)
+	require.NoError(t, err)
+	c := ggrpc.NewGordianGRPCClient(gc)
+
+	return Fixture{
+		Server: srv,
+		Client: c,
+
+		FinalizationStore: fs,
+		MirrorStore:       ms,
+	}
+}

gserver/internal/ggrpc/server.go

@@ -20,6 +20,7 @@ var _ GordianGRPCServer = (*GordianGRPC)(nil)
 
 type GordianGRPC struct {
 	UnimplementedGordianGRPCServer
+
 	log *slog.Logger
 
 	fs tmstore.FinalizationStore

gserver/internal/ggrpc/server_test.go

@@ -0,0 +1,34 @@
+package ggrpc_test
+
+import (
+	context "context"
+	"testing"
+
+	"github.com/gordian-engine/gcosmos/gserver/internal/ggrpc"
+	"github.com/gordian-engine/gcosmos/gserver/internal/ggrpc/ggrpctest"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGRPCServer_GetBlocksWatermark(t *testing.T) {
+	t.Parallel()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	fx := ggrpctest.NewFixture(t, ctx)
+	defer cancel()
+
+	require.NoError(t, fx.MirrorStore.SetNetworkHeightRound(
+		ctx,
+		10, 1,
+		9, 3,
+	))
+
+	resp, err := fx.Client.GetBlocksWatermark(ctx, new(ggrpc.CurrentBlockRequest))
+	require.NoError(t, err)
+
+	require.Equal(t, uint64(10), resp.VotingHeight)
+	require.Equal(t, uint32(1), resp.VotingRound)
+	require.Equal(t, uint64(9), resp.CommittingHeight)
+	require.Equal(t, uint32(3), resp.CommittingRound)
+}

internal/gci/command.go

@@ -175,11 +175,11 @@ func NewGcosmosCommand(
 		panic(fmt.Errorf("failed to enhance root command: %w", err))
 	}
 
+	shimGordianClient(rootCmd)
+
 	return rootCmd
 }
 
-// shimGordianClient used to be part of the old gcosmos command,
-// and we probably need to use this in NewGcosmosCommand.
 func shimGordianClient(cmd *cobra.Command) {
 	origPersistentPreRunE := cmd.PersistentPreRunE