Validate migration files (#18203)

JSON Schema validation for data used by Gitea during migrations

Discussion at https://forum.forgefriends.org/t/common-json-schema-for-repository-information/563

Co-authored-by: Loïc Dachary <loic@dachary.org>

modules/migration/file_format_test.go

@@ -0,0 +1,39 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migration
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/santhosh-tekuri/jsonschema/v5"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMigrationJSON_IssueOK(t *testing.T) {
+	issues := make([]*Issue, 0, 10)
+	err := Load("file_format_testdata/issue_a.json", &issues, true)
+	assert.NoError(t, err)
+	err = Load("file_format_testdata/issue_a.yml", &issues, true)
+	assert.NoError(t, err)
+}
+
+func TestMigrationJSON_IssueFail(t *testing.T) {
+	issues := make([]*Issue, 0, 10)
+	err := Load("file_format_testdata/issue_b.json", &issues, true)
+	if _, ok := err.(*jsonschema.ValidationError); ok {
+		errors := strings.Split(err.(*jsonschema.ValidationError).GoString(), "\n")
+		assert.Contains(t, errors[1], "missing properties")
+		assert.Contains(t, errors[1], "poster_id")
+	} else {
+		t.Fatalf("got: type %T with value %s, want: *jsonschema.ValidationError", err, err)
+	}
+}
+
+func TestMigrationJSON_MilestoneOK(t *testing.T) {
+	milestones := make([]*Milestone, 0, 10)
+	err := Load("file_format_testdata/milestones.json", &milestones, true)
+	assert.NoError(t, err)
+}