Checking non-exported migration method

driver/mongodb/example/mongodb_test.go

@@ -235,6 +235,27 @@ func TestMigrate(t *testing.T) {
 				Errors:           []error{gomethods.MissingMethodError("v001_non_existing_method_up")},
 			},
 		},
+		{
+			name: "v0 -> v1: not exported method aborts migration",
+			file: file.File{
+				Path:      "/foobar",
+				FileName:  "001_foobar.up.gm",
+				Version:   1,
+				Name:      "foobar",
+				Direction: direction.Up,
+				Content: []byte(`
+						V001_init_organizations_up
+						v001_not_exported_method_up
+						V001_init_users_up
+					`),
+			},
+			expectedResult: ExpectedMigrationResult{
+				Organizations:    []Organization{},
+				Organizations_v2: []Organization_v2{},
+				Users:            []User{},
+				Errors:           []error{gomethods.MethodNotExportedError("v001_not_exported_method_up")},
+			},
+		},
 		{
 			name: "v0 -> v1: wrong signature method aborts migration",
 			file: file.File{

driver/mongodb/example/sample_mongdb_migrator.go

@@ -140,6 +140,10 @@ func (r *SampleMongoDbMigrator) V002_change_user_cleo_to_cleopatra_down(session
 }
 
 // Wrong signature methods for testing
+func (r *SampleMongoDbMigrator) v001_not_exported_method_up(session *mgo.Session) error {
+	return nil
+}
+
 func (r *SampleMongoDbMigrator) V001_method_with_wrong_signature_up(s string) error {
 	return nil
 }

driver/mongodb/gomethods/gomethods_migrator.go

@@ -20,6 +20,12 @@ func (e WrongMethodSignatureError) Error() string {
 	return fmt.Sprintf("Method %s has wrong signature", string(e))
 }
 
+type MethodNotExportedError string
+
+func (e MethodNotExportedError) Error() string {
+	return fmt.Sprintf("Method %s is not exported", string(e))
+}
+
 type MethodInvocationFailedError struct {
 	MethodName string
 	Err        error

driver/mongodb/mongodb.go

@@ -142,14 +142,18 @@ func (driver *Driver) Migrate(f file.File, pipe chan interface{}) {
 }
 
 func (driver *Driver) Validate(methodName string) error {
-	method := reflect.ValueOf(driver.methodsReceiver).MethodByName(methodName)
+	methodWithReceiver, ok := reflect.TypeOf(driver.methodsReceiver).MethodByName(methodName)
-	if !method.IsValid() {
+	if !ok {
 		return gomethods.MissingMethodError(methodName)
 	}
+	if methodWithReceiver.PkgPath != "" {
+		return gomethods.MethodNotExportedError(methodName)
+	}
 
+	methodFunc := reflect.ValueOf(driver.methodsReceiver).MethodByName(methodName)
 	methodTemplate := func(*mgo.Session) error { return nil }
 
-	if method.Type() != reflect.TypeOf(methodTemplate) {
+	if methodFunc.Type() != reflect.TypeOf(methodTemplate) {
 		return gomethods.WrongMethodSignatureError(methodName)
 	}