feat(hooks): add OnTxBegin and runInTx for resolvespec and restheadspec

Every transaction the handlers open now fires OnTxBegin first, with the
transaction in hookCtx.Tx, via common.RunRequestTx.

pkg/resolvespec/on_tx_begin_test.go

@@ -0,0 +1,84 @@
+package resolvespec
+
+import (
+	"errors"
+	"net/http"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
+)
+
+// recordTxOrder records the order hooks fire in and the Tx each one saw.
+func recordTxOrder(h *Handler, beginErr error) (*[]string, *[]common.Database) {
+	var order []string
+	var txs []common.Database
+	h.Hooks().Register(OnTxBegin, func(ctx *HookContext) error {
+		order = append(order, "begin")
+		txs = append(txs, ctx.Tx)
+		return beginErr
+	})
+	h.Hooks().Register(BeforeDelete, func(ctx *HookContext) error {
+		order = append(order, "before_delete")
+		return nil
+	})
+	return &order, &txs
+}
+
+func TestOnTxBeginFiresOnceFirstOnTx(t *testing.T) {
+	cases := map[string]struct {
+		id   string
+		data interface{}
+		exec int
+	}{
+		"single": {id: "7", exec: 1},
+		"batch":  {data: []interface{}{"1", "2"}, exec: 2},
+	}
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			h, mock, _ := newDeleteHarness(t)
+			order, txs := recordTxOrder(h, nil)
+
+			mock.ExpectBegin()
+			if tc.id != "" {
+				mock.ExpectQuery(`SELECT`).WillReturnRows(sqlmock.NewRows([]string{"id", "name"}).AddRow(7, "a"))
+			}
+			for i := 0; i < tc.exec; i++ {
+				mock.ExpectExec(`DELETE FROM`).WillReturnResult(sqlmock.NewResult(0, 1))
+			}
+			mock.ExpectCommit()
+
+			if rec := runDelete(h, tc.id, tc.data); rec.Code != http.StatusOK {
+				t.Fatalf("status %d body %s", rec.Code, rec.Body)
+			}
+			if err := mock.ExpectationsWereMet(); err != nil {
+				t.Fatal(err)
+			}
+			if len(*txs) != 1 || (*txs)[0] == nil || (*txs)[0] == h.db {
+				t.Fatalf("OnTxBegin must fire once on the transaction, got %v", *txs)
+			}
+			if (*order)[0] != "begin" {
+				t.Fatalf("OnTxBegin must fire before other hooks, got %v", *order)
+			}
+		})
+	}
+}
+
+func TestOnTxBeginErrorRollsBackWithoutQueries(t *testing.T) {
+	h, mock, _ := newDeleteHarness(t)
+	order, _ := recordTxOrder(h, errors.New("no user"))
+
+	mock.ExpectBegin()
+	mock.ExpectRollback()
+
+	if rec := runDelete(h, "7", nil); rec.Code < http.StatusBadRequest {
+		t.Fatalf("status %d body %s", rec.Code, rec.Body)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+	if len(*order) != 1 {
+		t.Fatalf("no hook may run after a failed OnTxBegin, got %v", *order)
+	}
+}