Decouple unit test code from business code (#17623)

modules/convert/git_commit_test.go

@@ -10,6 +10,7 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/unittest"
 	"code.gitea.io/gitea/modules/git"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/util"
@@ -18,7 +19,7 @@ import (
 )
 
 func TestToCommitMeta(t *testing.T) {
-	assert.NoError(t, db.PrepareTestDatabase())
+	assert.NoError(t, unittest.PrepareTestDatabase())
 	headRepo := db.AssertExistsAndLoadBean(t, &models.Repository{ID: 1}).(*models.Repository)
 	sha1, _ := git.NewIDFromString("0000000000000000000000000000000000000000")
 	signature := &git.Signature{Name: "Test Signature", Email: "test@email.com", When: time.Unix(0, 0)}