chore: add tests for observable proxy

internal/datastore/memdb/memdb.go

@@ -27,7 +27,7 @@ const (
 	numAttempts              = 10
 )
 
-var errSerialization = errors.New("serialization error")
+var ErrSerialization = errors.New("serialization error")
 
 // DisableGC is a convenient constant for setting the garbage collection
 // interval high enough that it will never run.
@@ -154,7 +154,7 @@ func (mdb *memdbDatastore) ReadWriteTx(
 				defer mdb.Unlock()
 
 				if mdb.activeWriteTxn != nil {
-					err = errSerialization
+					err = ErrSerialization
 					return
 				}
 
@@ -181,7 +181,7 @@ func (mdb *memdbDatastore) ReadWriteTx(
 			}
 
 			// If the error was a serialization error, retry the transaction
-			if errors.Is(err, errSerialization) {
+			if errors.Is(err, ErrSerialization) {
 				mdb.Unlock()
 
 				// If we don't sleep here, we run out of retries instantaneously

internal/datastore/proxy/observable_test.go

@@ -0,0 +1,28 @@
+package proxy
+
+import (
+	"testing"
+	"time"
+
+	"github.com/authzed/spicedb/internal/datastore/memdb"
+	"github.com/authzed/spicedb/pkg/datastore"
+	"github.com/authzed/spicedb/pkg/datastore/test"
+)
+
+type observableTest struct{}
+
+func (obs observableTest) New(revisionQuantization, _, gcWindow time.Duration, watchBufferLength uint16) (datastore.Datastore, error) {
+	db, err := memdb.NewMemdbDatastore(watchBufferLength, revisionQuantization, gcWindow)
+	if err != nil {
+		return nil, err
+	}
+	return NewObservableDatastoreProxy(db), nil
+}
+
+func TestObservableProxy(t *testing.T) {
+	test.All(t, observableTest{})
+}
+
+func (p *observableProxy) ExampleRetryableError() error {
+	return memdb.ErrSerialization
+}