1 files changed, 143 insertions, 0 deletions
diff --git a/modules/repofiles/diff_test.go b/modules/repofiles/diff_test.go
new file mode 100644
index 0000000000..bc7d4ebad6
--- /dev/null
+++ b/modules/repofiles/diff_test.go
@@ -0,0 +1,143 @@
+// Copyright 2019 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 repofiles
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/test"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetDiffPreview(t *testing.T) {
+	models.PrepareTestEnv(t)
+	ctx := test.MockContext(t, "user2/repo1")
+	ctx.SetParams(":id", "1")
+	test.LoadRepo(t, ctx, 1)
+	test.LoadRepoCommit(t, ctx)
+	test.LoadUser(t, ctx, 2)
+	test.LoadGitRepo(t, ctx)
+	branch := ctx.Repo.Repository.DefaultBranch
+	treePath := "README.md"
+	content := "# repo1\n\nDescription for repo1\nthis is a new line"
+
+	expectedDiff := &models.Diff{
+		TotalAddition: 2,
+		TotalDeletion: 1,
+		Files: []*models.DiffFile{
+			{
+				Name:        "README.md",
+				OldName:     "README.md",
+				Index:       1,
+				Addition:    2,
+				Deletion:    1,
+				Type:        2,
+				IsCreated:   false,
+				IsDeleted:   false,
+				IsBin:       false,
+				IsLFSFile:   false,
+				IsRenamed:   false,
+				IsSubmodule: false,
+				Sections: []*models.DiffSection{
+					{
+						Name: "",
+						Lines: []*models.DiffLine{
+							{
+								LeftIdx:  0,
+								RightIdx: 0,
+								Type:     4,
+								Content:  "@@ -1,3 +1,4 @@",
+								Comments: nil,
+							},
+							{
+								LeftIdx:  1,
+								RightIdx: 1,
+								Type:     1,
+								Content:  " # repo1",
+								Comments: nil,
+							},
+							{
+								LeftIdx:  2,
+								RightIdx: 2,
+								Type:     1,
+								Content:  " ",
+								Comments: nil,
+							},
+							{
+								LeftIdx:  3,
+								RightIdx: 0,
+								Type:     3,
+								Content:  "-Description for repo1",
+								Comments: nil,
+							},
+							{
+								LeftIdx:  0,
+								RightIdx: 3,
+								Type:     2,
+								Content:  "+Description for repo1",
+								Comments: nil,
+							},
+							{
+								LeftIdx:  0,
+								RightIdx: 4,
+								Type:     2,
+								Content:  "+this is a new line",
+								Comments: nil,
+							},
+						},
+					},
+				},
+				IsIncomplete: false,
+			},
+		},
+		IsIncomplete: false,
+	}
+
+	t.Run("with given branch", func(t *testing.T) {
+		diff, err := GetDiffPreview(ctx.Repo.Repository, branch, treePath, content)
+		assert.Nil(t, err)
+		assert.EqualValues(t, expectedDiff, diff)
+	})
+
+	t.Run("empty branch, same results", func(t *testing.T) {
+		diff, err := GetDiffPreview(ctx.Repo.Repository, "", treePath, content)
+		assert.Nil(t, err)
+		assert.EqualValues(t, expectedDiff, diff)
+	})
+}
+
+func TestGetDiffPreviewErrors(t *testing.T) {
+	models.PrepareTestEnv(t)
+	ctx := test.MockContext(t, "user2/repo1")
+	ctx.SetParams(":id", "1")
+	test.LoadRepo(t, ctx, 1)
+	test.LoadRepoCommit(t, ctx)
+	test.LoadUser(t, ctx, 2)
+	test.LoadGitRepo(t, ctx)
+	branch := ctx.Repo.Repository.DefaultBranch
+	treePath := "README.md"
+	content := "# repo1\n\nDescription for repo1\nthis is a new line"
+
+	t.Run("empty repo", func(t *testing.T) {
+		diff, err := GetDiffPreview(&models.Repository{}, branch, treePath, content)
+		assert.Nil(t, diff)
+		assert.EqualError(t, err, "repository does not exist [id: 0, uid: 0, owner_name: , name: ]")
+	})
+
+	t.Run("bad branch", func(t *testing.T) {
+		badBranch := "bad_branch"
+		diff, err := GetDiffPreview(ctx.Repo.Repository, badBranch, treePath, content)
+		assert.Nil(t, diff)
+		assert.EqualError(t, err, "branch does not exist [name: "+badBranch+"]")
+	})
+
+	t.Run("empty treePath", func(t *testing.T) {
+		diff, err := GetDiffPreview(ctx.Repo.Repository, branch, "", content)
+		assert.Nil(t, diff)
+		assert.EqualError(t, err, "path is invalid [path: ]")
+	})
+}