add removal test

cayley.go

@@ -191,6 +191,28 @@ func main() {
 }
 
 func load(qw graph.QuadWriter, cfg *config.Config, path, typ string) error {
+	return decompressAndLoad(qw, cfg, path, typ, db.Load)
+}
+
+func removeAll(qw graph.QuadWriter, cfg *config.Config, path, typ string) error {
+	return decompressAndLoad(qw, cfg, path, typ, remove)
+}
+
+func remove(qw graph.QuadWriter, cfg *config.Config, dec quad.Unmarshaler) error {
+	for {
+		t, err := dec.Unmarshal()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		qw.RemoveQuad(t)
+	}
+	return nil
+}
+
+func decompressAndLoad(qw graph.QuadWriter, cfg *config.Config, path, typ string, loadFn func(graph.QuadWriter, *config.Config, quad.Unmarshaler) error) error {
 	var r io.Reader
 
 	if path == "" {

cayley_test.go

@@ -296,7 +296,8 @@ var m2_actors = movie2.Save("name","movie2").Follow(filmToActor)
 `
 
 var (
-	once sync.Once
+	create            sync.Once
+	deleteAndRecreate sync.Once
 	cfg               = &config.Config{
 		DatabasePath:    "30kmoviedata.nq.gz",
 		DatabaseType:    "memstore",
@@ -309,7 +310,7 @@ var (
 
 func prepare(t testing.TB) {
 	var err error
-	once.Do(func() {
+	create.Do(func() {
 		handle, err = db.Open(cfg)
 		if err != nil {
 			t.Fatalf("Failed to open %q: %v", cfg.DatabasePath, err)
@@ -324,8 +325,37 @@ func prepare(t testing.TB) {
 	})
 }
 
+func deletePrepare(t testing.TB) {
+	var err error
+	deleteAndRecreate.Do(func() {
+		prepare(t)
+		if !graph.IsPersistent(cfg.DatabaseType) {
+			err = removeAll(handle.QuadWriter, cfg, "", "cquad")
+			if err != nil {
+				t.Fatalf("Failed to remove %q: %v", cfg.DatabasePath, err)
+			}
+			err = load(handle.QuadWriter, cfg, "", "cquad")
+			if err != nil {
+				t.Fatalf("Failed to load %q: %v", cfg.DatabasePath, err)
+			}
+		}
+	})
+}
+
 func TestQueries(t *testing.T) {
 	prepare(t)
+	checkQueries(t)
+}
+
+func TestDeletedAndRecreatedQueries(t *testing.T) {
+	if testing.Short() {
+		t.Skip()
+	}
+	deletePrepare(t)
+	checkQueries(t)
+}
+
+func checkQueries(t *testing.T) {
 	for _, test := range benchmarkQueries {
 		if testing.Short() && test.long {
 			continue