Data layer restructuring (#997)

* Move query builders to sqlite package
* Add transaction system
* Wrap model resolvers in transaction
* Add error return value for StringSliceToIntSlice
* Update/refactor mutation resolvers
* Convert query builders
* Remove unused join types
* Add stash id unit tests
* Use WAL journal mode

pkg/sqlite/stash_id_test.go

@@ -0,0 +1,70 @@
+package sqlite_test
+
+import (
+	"testing"
+
+	"github.com/stashapp/stash/pkg/models"
+	"github.com/stretchr/testify/assert"
+)
+
+type stashIDReaderWriter interface {
+	GetStashIDs(performerID int) ([]*models.StashID, error)
+	UpdateStashIDs(performerID int, stashIDs []models.StashID) error
+}
+
+func testStashIDReaderWriter(t *testing.T, r stashIDReaderWriter, id int) {
+	// ensure no stash IDs to begin with
+	testNoStashIDs(t, r, id)
+
+	// ensure GetStashIDs with non-existing also returns none
+	testNoStashIDs(t, r, -1)
+
+	// add stash ids
+	const stashIDStr = "stashID"
+	const endpoint = "endpoint"
+	stashID := models.StashID{
+		StashID:  stashIDStr,
+		Endpoint: endpoint,
+	}
+
+	// update stash ids and ensure was updated
+	if err := r.UpdateStashIDs(id, []models.StashID{stashID}); err != nil {
+		t.Error(err.Error())
+	}
+
+	testStashIDs(t, r, id, []*models.StashID{&stashID})
+
+	// update non-existing id - should return error
+	if err := r.UpdateStashIDs(-1, []models.StashID{stashID}); err == nil {
+		t.Error("expected error when updating non-existing id")
+	}
+
+	// remove stash ids and ensure was updated
+	if err := r.UpdateStashIDs(id, []models.StashID{}); err != nil {
+		t.Error(err.Error())
+	}
+
+	testNoStashIDs(t, r, id)
+}
+
+func testNoStashIDs(t *testing.T, r stashIDReaderWriter, id int) {
+	t.Helper()
+	stashIDs, err := r.GetStashIDs(id)
+	if err != nil {
+		t.Error(err.Error())
+		return
+	}
+
+	assert.Len(t, stashIDs, 0)
+}
+
+func testStashIDs(t *testing.T, r stashIDReaderWriter, id int, expected []*models.StashID) {
+	t.Helper()
+	stashIDs, err := r.GetStashIDs(id)
+	if err != nil {
+		t.Error(err.Error())
+		return
+	}
+
+	assert.Equal(t, stashIDs, expected)
+}