[MM-8421] Fix tiff preview - backend (#10170)

api4/file.go

@@ -42,6 +42,7 @@ var MEDIA_CONTENT_TYPES = [...]string{
 	"image/png",
 	"image/bmp",
 	"image/gif",
+	"image/tiff",
 	"video/avi",
 	"video/mpeg",
 	"video/mp4",

api4/file_test.go

@@ -346,14 +346,14 @@ func TestUploadFiles(t *testing.T) {
 		// Upload a bunch of files, mixed images and non-images
 		{
 			title:             "Happy",
-			names:             []string{"test.png", "testgif.gif", "testplugin.tar.gz", "test-search.md"},
+			names:             []string{"test.png", "testgif.gif", "testplugin.tar.gz", "test-search.md", "test.tiff"},
 			expectedCreatorId: th.BasicUser.Id,
 		},
 		// Upload a bunch of files, with clientIds
 		{
 			title:             "Happy client_ids",
-			names:             []string{"test.png", "testgif.gif", "testplugin.tar.gz", "test-search.md"},
-			clientIds:         []string{"1", "2", "3", "4"},
+			names:             []string{"test.png", "testgif.gif", "testplugin.tar.gz", "test-search.md", "test.tiff"},
+			clientIds:         []string{"1", "2", "3", "4", "5"},
 			expectedCreatorId: th.BasicUser.Id,
 		},
 		// Upload a bunch of images. testgif.gif is an animated GIF,
@@ -478,6 +478,18 @@ func TestUploadFiles(t *testing.T) {
 			expectedImageHasPreview:     []bool{true},
 			expectedCreatorId:           th.BasicUser.Id,
 		},
+		// TIFF preview test
+		{
+			title:                       "Happy image thumbnail/preview 9",
+			names:                       []string{"test.tiff"},
+			expectedImageThumbnailNames: []string{"test_expected_thumb.tiff"},
+			expectedImagePreviewNames:   []string{"test_expected_preview.tiff"},
+			expectImage:                 true,
+			expectedImageWidths:         []int{701},
+			expectedImageHeights:        []int{701},
+			expectedImageHasPreview:     []bool{true},
+			expectedCreatorId:           th.BasicUser.Id,
+		},
 		{
 			title:             "Happy admin",
 			client:            th.SystemAdminClient,