Add flexible test setup

pkg/conn/gorilla/gorilla.go

@@ -239,6 +239,8 @@ func (ws *WebSocket) initialize() {
 				var res rpc.RPCResponse
 				err := ws.read(&res)
 				if err != nil {
+					// TODO: Handle error correctly, otherwise this can panic
+					// after 1000 tries in a tight loop.
 					ws.logger.Error(err.Error())
 					continue
 				}

query_test.go

@@ -0,0 +1,90 @@
+package surrealdb
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/surrealdb/surrealdb.go/pkg/marshal"
+)
+
+// TestSurrealDBLocal runs a local SurrealDB instance by calling
+// `NewTestSurrealDB(t)`, which is a dedicated SurrealDB instance with no data.
+func TestSurrealDBLocal(t *testing.T) {
+	t.Parallel()
+	cases := map[string]struct {
+		schema              []string
+		dbInteraction       func(*testing.T, *DB)
+		keepServerUponError bool
+	}{
+		"first case": {
+			schema: []string{
+				"CREATE user:x SET name = 'xxxx'",
+				"CREATE user:y SET name = 'yyyy'",
+			},
+			dbInteraction: func(t *testing.T, db *DB) {
+				data, err := db.Select("user")
+				if err != nil {
+					t.Fatalf("failed to select, %v", err)
+				}
+				type dataholder struct {
+					ID   string `json:"id,omitempty"`
+					Name string `json:"name,omitempty"`
+				}
+				d, err := marshal.SmartUnmarshal[dataholder](data, nil)
+				if err != nil {
+					t.Fatal(err)
+				}
+				want := []dataholder{
+					{ID: "user:x", Name: "xxxx"},
+					{ID: "user:y", Name: "yyyy"},
+				}
+				if diff := cmp.Diff(want, d); diff != "" {
+					t.Errorf("Result mismatch (-want +got):\n%s", diff)
+				}
+			},
+		},
+		"second case": {
+			schema: []string{
+				"CREATE user:x SET name = 'xxxx'",
+				"CREATE user:y SET name = 'yyyy'",
+			},
+			dbInteraction: func(t *testing.T, db *DB) {
+			},
+		},
+		"third case": {
+			schema: []string{
+				"CREATE user:x SET name = 'xxxx'",
+				"CREATE user:y SET name = 'yyyy'",
+				"CREATE user:y SET name = 'yyyy'", // Should fail
+			},
+			dbInteraction: func(t *testing.T, db *DB) {
+			},
+		},
+	}
+
+	for name, tc := range cases {
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			endpoint, db, cancel := NewTestSurrealDB(t)
+			defer func() {
+				// If test case failed, keep the server running for further
+				// investigation. This could be something we can turn on with
+				// some special flag.
+				if tc.keepServerUponError && t.Failed() {
+					return
+				}
+				// Otherwise cleanup the server.
+				cancel()
+			}()
+			_ = endpoint // Not used for this test.
+
+			for _, s := range tc.schema {
+				db.Prepare(t, s)
+			}
+
+			tc.dbInteraction(t, db.DB)
+		})
+	}
+}