Add latest changes from gitlab-org/gitlab@14-0-stable-eev14.0.0-rc42

8 files changed, 465 insertions, 369 deletions

diff --git a/spec/frontend/diffs/components/diff_content_spec.js b/spec/frontend/diffs/components/diff_content_spec.js
index db4d69f0176..7012889440c 100644
--- a/spec/frontend/diffs/components/diff_content_spec.js
+++ b/spec/frontend/diffs/components/diff_content_spec.js
@@ -73,6 +73,7 @@ describe('DiffContent', () => {
             isParallelView: isParallelViewGetterMock,
             getCommentFormForDiffFile: getCommentFormForDiffFileGetterMock,
             diffLines: () => () => [...diffFileMockData.parallel_diff_lines],
+            fileLineCodequality: () => () => [],
           },
           actions: {
             saveDiffDiscussion: saveDiffDiscussionMock,
diff --git a/spec/frontend/diffs/components/diff_stats_spec.js b/spec/frontend/diffs/components/diff_stats_spec.js
index 504158fb7fc..4ef1ec55cb0 100644
--- a/spec/frontend/diffs/components/diff_stats_spec.js
+++ b/spec/frontend/diffs/components/diff_stats_spec.js
@@ -1,6 +1,9 @@
 import { GlIcon } from '@gitlab/ui';
 import { shallowMount } from '@vue/test-utils';
+import { extendedWrapper } from 'helpers/vue_test_utils_helper';
+
 import DiffStats from '~/diffs/components/diff_stats.vue';
+import mockDiffFile from '../mock_data/diff_file';
 
 const TEST_ADDED_LINES = 100;
 const TEST_REMOVED_LINES = 200;
@@ -11,13 +14,15 @@ describe('diff_stats', () => {
   let wrapper;
 
   const createComponent = (props = {}) => {
-    wrapper = shallowMount(DiffStats, {
-      propsData: {
-        addedLines: TEST_ADDED_LINES,
-        removedLines: TEST_REMOVED_LINES,
-        ...props,
-      },
-    });
+    wrapper = extendedWrapper(
+      shallowMount(DiffStats, {
+        propsData: {
+          addedLines: TEST_ADDED_LINES,
+          removedLines: TEST_REMOVED_LINES,
+          ...props,
+        },
+      }),
+    );
   };
 
   describe('diff stats group', () => {
@@ -38,15 +43,43 @@ describe('diff_stats', () => {
     });
   });
 
+  describe('bytes changes', () => {
+    let file;
+    const getBytesContainer = () => wrapper.find('.diff-stats > div:first-child');
+
+    beforeEach(() => {
+      file = {
+        ...mockDiffFile,
+        viewer: {
+          ...mockDiffFile.viewer,
+          name: 'not_diffable',
+        },
+      };
+
+      createComponent({ diffFile: file });
+    });
+
+    it("renders the bytes changes instead of line changes when the file isn't diffable", () => {
+      const content = getBytesContainer();
+
+      expect(content.classes('gl-text-green-600')).toBe(true);
+      expect(content.text()).toBe('+1.00 KiB (+100%)');
+    });
+  });
+
   describe('line changes', () => {
-    const findFileLine = (name) => wrapper.find(name);
+    const findFileLine = (name) => wrapper.findByTestId(name);
+
+    beforeEach(() => {
+      createComponent();
+    });
 
     it('shows the amount of lines added', () => {
-      expect(findFileLine('.js-file-addition-line').text()).toBe(TEST_ADDED_LINES.toString());
+      expect(findFileLine('js-file-addition-line').text()).toBe(TEST_ADDED_LINES.toString());
     });
 
     it('shows the amount of lines removed', () => {
-      expect(findFileLine('.js-file-deletion-line').text()).toBe(TEST_REMOVED_LINES.toString());
+      expect(findFileLine('js-file-deletion-line').text()).toBe(TEST_REMOVED_LINES.toString());
     });
   });
 
diff --git a/spec/frontend/diffs/components/settings_dropdown_spec.js b/spec/frontend/diffs/components/settings_dropdown_spec.js
index feac88cb802..43b9c5871a6 100644
--- a/spec/frontend/diffs/components/settings_dropdown_spec.js
+++ b/spec/frontend/diffs/components/settings_dropdown_spec.js
@@ -142,7 +142,6 @@ describe('Diff settings dropdown component', () => {
 
       expect(store.dispatch).toHaveBeenCalledWith('diffs/setShowWhitespace', {
         showWhitespace: !checked,
-        pushState: true,
       });
     });
   });
diff --git a/spec/frontend/diffs/mock_data/diff_file.js b/spec/frontend/diffs/mock_data/diff_file.js
index cef776c885a..9ebcd5ef26b 100644
--- a/spec/frontend/diffs/mock_data/diff_file.js
+++ b/spec/frontend/diffs/mock_data/diff_file.js
@@ -19,6 +19,8 @@ export default {
   renamed_file: false,
   old_path: 'CHANGELOG',
   new_path: 'CHANGELOG',
+  old_size: 1024,
+  new_size: 2048,
   mode_changed: false,
   a_mode: '100644',
   b_mode: '100644',
diff --git a/spec/frontend/diffs/store/actions_spec.js b/spec/frontend/diffs/store/actions_spec.js
index f46a42fae7a..14f8e090be9 100644
--- a/spec/frontend/diffs/store/actions_spec.js
+++ b/spec/frontend/diffs/store/actions_spec.js
@@ -9,8 +9,6 @@ import {
   INLINE_DIFF_VIEW_TYPE,
   PARALLEL_DIFF_VIEW_TYPE,
   DIFFS_PER_PAGE,
-  DIFF_WHITESPACE_COOKIE_NAME,
-  SHOW_WHITESPACE,
 } from '~/diffs/constants';
 import {
   setBaseConfig,
@@ -54,7 +52,8 @@ import {
 } from '~/diffs/store/actions';
 import * as types from '~/diffs/store/mutation_types';
 import * as utils from '~/diffs/store/utils';
-import { deprecatedCreateFlash as createFlash } from '~/flash';
+import * as workerUtils from '~/diffs/utils/workers';
+import createFlash from '~/flash';
 import axios from '~/lib/utils/axios_utils';
 import * as commonUtils from '~/lib/utils/common_utils';
 import { mergeUrlParams } from '~/lib/utils/url_utility';
@@ -252,7 +251,10 @@ describe('DiffsStoreActions', () => {
           { type: types.SET_MERGE_REQUEST_DIFFS, payload: diffMetadata.merge_request_diffs },
           { type: types.SET_DIFF_METADATA, payload: noFilesData },
           // Workers are synchronous in Jest environment (see https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58805)
-          { type: types.SET_TREE_DATA, payload: utils.generateTreeList(diffMetadata.diff_files) },
+          {
+            type: types.SET_TREE_DATA,
+            payload: workerUtils.generateTreeList(diffMetadata.diff_files),
+          },
         ],
         [],
         () => {
@@ -293,7 +295,9 @@ describe('DiffsStoreActions', () => {
 
       testAction(fetchCoverageFiles, {}, { endpointCoverage }, [], [], () => {
         expect(createFlash).toHaveBeenCalledTimes(1);
-        expect(createFlash).toHaveBeenCalledWith(expect.stringMatching('Something went wrong'));
+        expect(createFlash).toHaveBeenCalledWith({
+          message: expect.stringMatching('Something went wrong'),
+        });
         done();
       });
     });
@@ -1013,14 +1017,26 @@ describe('DiffsStoreActions', () => {
   });
 
   describe('setShowWhitespace', () => {
+    const endpointUpdateUser = 'user/prefs';
+    let putSpy;
+    let mock;
+
     beforeEach(() => {
+      mock = new MockAdapter(axios);
+      putSpy = jest.spyOn(axios, 'put');
+
+      mock.onPut(endpointUpdateUser).reply(200, {});
       jest.spyOn(eventHub, '$emit').mockImplementation();
     });
 
+    afterEach(() => {
+      mock.restore();
+    });
+
     it('commits SET_SHOW_WHITESPACE', (done) => {
       testAction(
         setShowWhitespace,
-        { showWhitespace: true },
+        { showWhitespace: true, updateDatabase: false },
         {},
         [{ type: types.SET_SHOW_WHITESPACE, payload: true }],
         [],
@@ -1028,32 +1044,20 @@ describe('DiffsStoreActions', () => {
       );
     });
 
-    it('sets cookie', () => {
-      setShowWhitespace({ commit() {} }, { showWhitespace: true });
-
-      expect(Cookies.get(DIFF_WHITESPACE_COOKIE_NAME)).toEqual(SHOW_WHITESPACE);
-    });
-
-    it('calls history pushState', () => {
-      setShowWhitespace({ commit() {} }, { showWhitespace: true, pushState: true });
-
-      expect(window.history.pushState).toHaveBeenCalled();
-    });
-
-    it('calls history pushState with merged params', () => {
-      window.history.pushState({}, '', '?test=1');
-
-      setShowWhitespace({ commit() {} }, { showWhitespace: true, pushState: true });
-
-      expect(
-        window.history.pushState.mock.calls[window.history.pushState.mock.calls.length - 1][2],
-      ).toMatch(/(.*)\?test=1&w=0/);
+    it('saves to the database', async () => {
+      await setShowWhitespace(
+        { state: { endpointUpdateUser }, commit() {} },
+        { showWhitespace: true, updateDatabase: true },
+      );
 
-      window.history.pushState({}, '', '?');
+      expect(putSpy).toHaveBeenCalledWith(endpointUpdateUser, { show_whitespace_in_diffs: true });
     });
 
-    it('emits eventHub event', () => {
-      setShowWhitespace({ commit() {} }, { showWhitespace: true, pushState: true });
+    it('emits eventHub event', async () => {
+      await setShowWhitespace(
+        { state: {}, commit() {} },
+        { showWhitespace: true, updateDatabase: false },
+      );
 
       expect(eventHub.$emit).toHaveBeenCalledWith('refetchDiffData');
     });
diff --git a/spec/frontend/diffs/store/utils_spec.js b/spec/frontend/diffs/store/utils_spec.js
index 6af38590610..73de0a6d381 100644
--- a/spec/frontend/diffs/store/utils_spec.js
+++ b/spec/frontend/diffs/store/utils_spec.js
@@ -685,141 +685,6 @@ describe('DiffsStoreUtils', () => {
     });
   });
 
-  describe('generateTreeList', () => {
-    let files;
-
-    beforeAll(() => {
-      files = [
-        {
-          new_path: 'app/index.js',
-          deleted_file: false,
-          new_file: false,
-          removed_lines: 10,
-          added_lines: 0,
-          file_hash: 'test',
-        },
-        {
-          new_path: 'app/test/index.js',
-          deleted_file: false,
-          new_file: true,
-          removed_lines: 0,
-          added_lines: 0,
-          file_hash: 'test',
-        },
-        {
-          new_path: 'app/test/filepathneedstruncating.js',
-          deleted_file: false,
-          new_file: true,
-          removed_lines: 0,
-          added_lines: 0,
-          file_hash: 'test',
-        },
-        {
-          new_path: 'package.json',
-          deleted_file: true,
-          new_file: false,
-          removed_lines: 0,
-          added_lines: 0,
-          file_hash: 'test',
-        },
-      ];
-    });
-
-    it('creates a tree of files', () => {
-      const { tree } = utils.generateTreeList(files);
-
-      expect(tree).toEqual([
-        {
-          key: 'app',
-          path: 'app',
-          name: 'app',
-          type: 'tree',
-          tree: [
-            {
-              addedLines: 0,
-              changed: true,
-              deleted: false,
-              fileHash: 'test',
-              key: 'app/index.js',
-              name: 'index.js',
-              parentPath: 'app/',
-              path: 'app/index.js',
-              removedLines: 10,
-              tempFile: false,
-              type: 'blob',
-              tree: [],
-            },
-            {
-              key: 'app/test',
-              path: 'app/test',
-              name: 'test',
-              type: 'tree',
-              opened: true,
-              tree: [
-                {
-                  addedLines: 0,
-                  changed: true,
-                  deleted: false,
-                  fileHash: 'test',
-                  key: 'app/test/index.js',
-                  name: 'index.js',
-                  parentPath: 'app/test/',
-                  path: 'app/test/index.js',
-                  removedLines: 0,
-                  tempFile: true,
-                  type: 'blob',
-                  tree: [],
-                },
-                {
-                  addedLines: 0,
-                  changed: true,
-                  deleted: false,
-                  fileHash: 'test',
-                  key: 'app/test/filepathneedstruncating.js',
-                  name: 'filepathneedstruncating.js',
-                  parentPath: 'app/test/',
-                  path: 'app/test/filepathneedstruncating.js',
-                  removedLines: 0,
-                  tempFile: true,
-                  type: 'blob',
-                  tree: [],
-                },
-              ],
-            },
-          ],
-          opened: true,
-        },
-        {
-          key: 'package.json',
-          parentPath: '/',
-          path: 'package.json',
-          name: 'package.json',
-          type: 'blob',
-          changed: true,
-          tempFile: false,
-          deleted: true,
-          fileHash: 'test',
-          addedLines: 0,
-          removedLines: 0,
-          tree: [],
-        },
-      ]);
-    });
-
-    it('creates flat list of blobs & folders', () => {
-      const { treeEntries } = utils.generateTreeList(files);
-
-      expect(Object.keys(treeEntries)).toEqual([
-        'app',
-        'app/index.js',
-        'app/test',
-        'app/test/index.js',
-        'app/test/filepathneedstruncating.js',
-        'package.json',
-      ]);
-    });
-  });
-
   describe('getDiffMode', () => {
     it('returns mode when matched in file', () => {
       expect(
@@ -842,177 +707,6 @@ describe('DiffsStoreUtils', () => {
     });
   });
 
-  describe('getLowestSingleFolder', () => {
-    it('returns path and tree of lowest single folder tree', () => {
-      const folder = {
-        name: 'app',
-        type: 'tree',
-        tree: [
-          {
-            name: 'javascripts',
-            type: 'tree',
-            tree: [
-              {
-                type: 'blob',
-                name: 'index.js',
-              },
-            ],
-          },
-        ],
-      };
-      const { path, treeAcc } = utils.getLowestSingleFolder(folder);
-
-      expect(path).toEqual('app/javascripts');
-      expect(treeAcc).toEqual([
-        {
-          type: 'blob',
-          name: 'index.js',
-        },
-      ]);
-    });
-
-    it('returns passed in folders path & tree when more than tree exists', () => {
-      const folder = {
-        name: 'app',
-        type: 'tree',
-        tree: [
-          {
-            name: 'spec',
-            type: 'blob',
-            tree: [],
-          },
-        ],
-      };
-      const { path, treeAcc } = utils.getLowestSingleFolder(folder);
-
-      expect(path).toEqual('app');
-      expect(treeAcc).toBeNull();
-    });
-  });
-
-  describe('flattenTree', () => {
-    it('returns flattened directory structure', () => {
-      const tree = [
-        {
-          type: 'tree',
-          name: 'app',
-          tree: [
-            {
-              type: 'tree',
-              name: 'javascripts',
-              tree: [
-                {
-                  type: 'blob',
-                  name: 'index.js',
-                  tree: [],
-                },
-              ],
-            },
-          ],
-        },
-        {
-          type: 'tree',
-          name: 'ee',
-          tree: [
-            {
-              type: 'tree',
-              name: 'lib',
-              tree: [
-                {
-                  type: 'tree',
-                  name: 'ee',
-                  tree: [
-                    {
-                      type: 'tree',
-                      name: 'gitlab',
-                      tree: [
-                        {
-                          type: 'tree',
-                          name: 'checks',
-                          tree: [
-                            {
-                              type: 'tree',
-                              name: 'longtreenametomakepath',
-                              tree: [
-                                {
-                                  type: 'blob',
-                                  name: 'diff_check.rb',
-                                  tree: [],
-                                },
-                              ],
-                            },
-                          ],
-                        },
-                      ],
-                    },
-                  ],
-                },
-              ],
-            },
-          ],
-        },
-        {
-          type: 'tree',
-          name: 'spec',
-          tree: [
-            {
-              type: 'tree',
-              name: 'javascripts',
-              tree: [],
-            },
-            {
-              type: 'blob',
-              name: 'index_spec.js',
-              tree: [],
-            },
-          ],
-        },
-      ];
-      const flattened = utils.flattenTree(tree);
-
-      expect(flattened).toEqual([
-        {
-          type: 'tree',
-          name: 'app/javascripts',
-          tree: [
-            {
-              type: 'blob',
-              name: 'index.js',
-              tree: [],
-            },
-          ],
-        },
-        {
-          type: 'tree',
-          name: 'ee/lib/…/…/…/longtreenametomakepath',
-          tree: [
-            {
-              name: 'diff_check.rb',
-              tree: [],
-              type: 'blob',
-            },
-          ],
-        },
-        {
-          type: 'tree',
-          name: 'spec',
-          tree: [
-            {
-              type: 'tree',
-              name: 'javascripts',
-              tree: [],
-            },
-            {
-              type: 'blob',
-              name: 'index_spec.js',
-              tree: [],
-            },
-          ],
-        },
-      ]);
-    });
-  });
-
   describe('convertExpandLines', () => {
     it('converts expanded lines to normal lines', () => {
       const diffLines = [
@@ -1058,28 +752,6 @@ describe('DiffsStoreUtils', () => {
     });
   });
 
-  describe('getDefaultWhitespace', () => {
-    it('defaults to true if querystring and cookie are undefined', () => {
-      expect(utils.getDefaultWhitespace()).toBe(true);
-    });
-
-    it('returns false if querystring is `1`', () => {
-      expect(utils.getDefaultWhitespace('1', '0')).toBe(false);
-    });
-
-    it('returns true if querystring is `0`', () => {
-      expect(utils.getDefaultWhitespace('0', undefined)).toBe(true);
-    });
-
-    it('returns false if cookie is `1`', () => {
-      expect(utils.getDefaultWhitespace(undefined, '1')).toBe(false);
-    });
-
-    it('returns true if cookie is `0`', () => {
-      expect(utils.getDefaultWhitespace(undefined, '0')).toBe(true);
-    });
-  });
-
   describe('isAdded', () => {
     it.each`
       type               | expected
diff --git a/spec/frontend/diffs/utils/diff_file_spec.js b/spec/frontend/diffs/utils/diff_file_spec.js
index c6cfdfced65..3223b6c2dab 100644
--- a/spec/frontend/diffs/utils/diff_file_spec.js
+++ b/spec/frontend/diffs/utils/diff_file_spec.js
@@ -1,4 +1,11 @@
-import { prepareRawDiffFile, getShortShaFromFile } from '~/diffs/utils/diff_file';
+import {
+  prepareRawDiffFile,
+  getShortShaFromFile,
+  stats,
+  isNotDiffable,
+} from '~/diffs/utils/diff_file';
+import { diffViewerModes } from '~/ide/constants';
+import mockDiffFile from '../mock_data/diff_file';
 
 function getDiffFiles() {
   const loadFull = 'namespace/project/-/merge_requests/12345/diff_for_path?file_identifier=abc';
@@ -154,4 +161,73 @@ describe('diff_file utilities', () => {
       expect(getShortShaFromFile({ content_sha: cs })).toBe(response);
     });
   });
+
+  describe('stats', () => {
+    const noFile = [
+      "returns empty stats when the file isn't provided",
+      undefined,
+      {
+        text: '',
+        percent: 0,
+        changed: 0,
+        classes: '',
+        sign: '',
+        valid: false,
+      },
+    ];
+    const validFile = [
+      'computes the correct stats from a file',
+      mockDiffFile,
+      {
+        changed: 1024,
+        percent: 100,
+        classes: 'gl-text-green-600',
+        sign: '+',
+        text: '+1.00 KiB (+100%)',
+        valid: true,
+      },
+    ];
+    const negativeChange = [
+      'computed the correct states from a file with a negative size change',
+      {
+        ...mockDiffFile,
+        new_size: 0,
+        old_size: 1024,
+      },
+      {
+        changed: -1024,
+        percent: -100,
+        classes: 'gl-text-red-500',
+        sign: '',
+        text: '-1.00 KiB (-100%)',
+        valid: true,
+      },
+    ];
+
+    it.each([noFile, validFile, negativeChange])('%s', (_, file, output) => {
+      expect(stats(file)).toEqual(output);
+    });
+  });
+
+  describe('isNotDiffable', () => {
+    it.each`
+      bool     | vw
+      ${true}  | ${diffViewerModes.not_diffable}
+      ${false} | ${diffViewerModes.text}
+      ${false} | ${diffViewerModes.image}
+    `('returns $bool when the viewer is $vw', ({ bool, vw }) => {
+      expect(isNotDiffable({ viewer: { name: vw } })).toBe(bool);
+    });
+
+    it.each`
+      file
+      ${undefined}
+      ${null}
+      ${{}}
+      ${{ viewer: undefined }}
+      ${{ viewer: null }}
+    `('reports `false` when the file is `$file`', ({ file }) => {
+      expect(isNotDiffable(file)).toBe(false);
+    });
+  });
 });
diff --git a/spec/frontend/diffs/utils/workers_spec.js b/spec/frontend/diffs/utils/workers_spec.js
new file mode 100644
index 00000000000..25d8183b777
--- /dev/null
+++ b/spec/frontend/diffs/utils/workers_spec.js
@@ -0,0 +1,309 @@
+import { generateTreeList, getLowestSingleFolder, flattenTree } from '~/diffs/utils/workers';
+
+describe('~/diffs/utils/workers', () => {
+  describe('generateTreeList', () => {
+    let files;
+
+    beforeAll(() => {
+      files = [
+        {
+          new_path: 'app/index.js',
+          deleted_file: false,
+          new_file: false,
+          removed_lines: 10,
+          added_lines: 0,
+          file_hash: 'test',
+        },
+        {
+          new_path: 'app/test/index.js',
+          deleted_file: false,
+          new_file: true,
+          removed_lines: 0,
+          added_lines: 0,
+          file_hash: 'test',
+        },
+        {
+          new_path: 'app/test/filepathneedstruncating.js',
+          deleted_file: false,
+          new_file: true,
+          removed_lines: 0,
+          added_lines: 0,
+          file_hash: 'test',
+        },
+        {
+          new_path: 'package.json',
+          deleted_file: true,
+          new_file: false,
+          removed_lines: 0,
+          added_lines: 0,
+          file_hash: 'test',
+        },
+      ];
+    });
+
+    it('creates a tree of files', () => {
+      const { tree } = generateTreeList(files);
+
+      expect(tree).toEqual([
+        {
+          key: 'app',
+          path: 'app',
+          name: 'app',
+          type: 'tree',
+          tree: [
+            {
+              addedLines: 0,
+              changed: true,
+              deleted: false,
+              fileHash: 'test',
+              key: 'app/index.js',
+              name: 'index.js',
+              parentPath: 'app/',
+              path: 'app/index.js',
+              removedLines: 10,
+              tempFile: false,
+              type: 'blob',
+              tree: [],
+            },
+            {
+              key: 'app/test',
+              path: 'app/test',
+              name: 'test',
+              type: 'tree',
+              opened: true,
+              tree: [
+                {
+                  addedLines: 0,
+                  changed: true,
+                  deleted: false,
+                  fileHash: 'test',
+                  key: 'app/test/index.js',
+                  name: 'index.js',
+                  parentPath: 'app/test/',
+                  path: 'app/test/index.js',
+                  removedLines: 0,
+                  tempFile: true,
+                  type: 'blob',
+                  tree: [],
+                },
+                {
+                  addedLines: 0,
+                  changed: true,
+                  deleted: false,
+                  fileHash: 'test',
+                  key: 'app/test/filepathneedstruncating.js',
+                  name: 'filepathneedstruncating.js',
+                  parentPath: 'app/test/',
+                  path: 'app/test/filepathneedstruncating.js',
+                  removedLines: 0,
+                  tempFile: true,
+                  type: 'blob',
+                  tree: [],
+                },
+              ],
+            },
+          ],
+          opened: true,
+        },
+        {
+          key: 'package.json',
+          parentPath: '/',
+          path: 'package.json',
+          name: 'package.json',
+          type: 'blob',
+          changed: true,
+          tempFile: false,
+          deleted: true,
+          fileHash: 'test',
+          addedLines: 0,
+          removedLines: 0,
+          tree: [],
+        },
+      ]);
+    });
+
+    it('creates flat list of blobs & folders', () => {
+      const { treeEntries } = generateTreeList(files);
+
+      expect(Object.keys(treeEntries)).toEqual([
+        'app',
+        'app/index.js',
+        'app/test',
+        'app/test/index.js',
+        'app/test/filepathneedstruncating.js',
+        'package.json',
+      ]);
+    });
+  });
+
+  describe('getLowestSingleFolder', () => {
+    it('returns path and tree of lowest single folder tree', () => {
+      const folder = {
+        name: 'app',
+        type: 'tree',
+        tree: [
+          {
+            name: 'javascripts',
+            type: 'tree',
+            tree: [
+              {
+                type: 'blob',
+                name: 'index.js',
+              },
+            ],
+          },
+        ],
+      };
+      const { path, treeAcc } = getLowestSingleFolder(folder);
+
+      expect(path).toEqual('app/javascripts');
+      expect(treeAcc).toEqual([
+        {
+          type: 'blob',
+          name: 'index.js',
+        },
+      ]);
+    });
+
+    it('returns passed in folders path & tree when more than tree exists', () => {
+      const folder = {
+        name: 'app',
+        type: 'tree',
+        tree: [
+          {
+            name: 'spec',
+            type: 'blob',
+            tree: [],
+          },
+        ],
+      };
+      const { path, treeAcc } = getLowestSingleFolder(folder);
+
+      expect(path).toEqual('app');
+      expect(treeAcc).toBeNull();
+    });
+  });
+
+  describe('flattenTree', () => {
+    it('returns flattened directory structure', () => {
+      const tree = [
+        {
+          type: 'tree',
+          name: 'app',
+          tree: [
+            {
+              type: 'tree',
+              name: 'javascripts',
+              tree: [
+                {
+                  type: 'blob',
+                  name: 'index.js',
+                  tree: [],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          type: 'tree',
+          name: 'ee',
+          tree: [
+            {
+              type: 'tree',
+              name: 'lib',
+              tree: [
+                {
+                  type: 'tree',
+                  name: 'ee',
+                  tree: [
+                    {
+                      type: 'tree',
+                      name: 'gitlab',
+                      tree: [
+                        {
+                          type: 'tree',
+                          name: 'checks',
+                          tree: [
+                            {
+                              type: 'tree',
+                              name: 'longtreenametomakepath',
+                              tree: [
+                                {
+                                  type: 'blob',
+                                  name: 'diff_check.rb',
+                                  tree: [],
+                                },
+                              ],
+                            },
+                          ],
+                        },
+                      ],
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          type: 'tree',
+          name: 'spec',
+          tree: [
+            {
+              type: 'tree',
+              name: 'javascripts',
+              tree: [],
+            },
+            {
+              type: 'blob',
+              name: 'index_spec.js',
+              tree: [],
+            },
+          ],
+        },
+      ];
+      const flattened = flattenTree(tree);
+
+      expect(flattened).toEqual([
+        {
+          type: 'tree',
+          name: 'app/javascripts',
+          tree: [
+            {
+              type: 'blob',
+              name: 'index.js',
+              tree: [],
+            },
+          ],
+        },
+        {
+          type: 'tree',
+          name: 'ee/lib/…/…/…/longtreenametomakepath',
+          tree: [
+            {
+              name: 'diff_check.rb',
+              tree: [],
+              type: 'blob',
+            },
+          ],
+        },
+        {
+          type: 'tree',
+          name: 'spec',
+          tree: [
+            {
+              type: 'tree',
+              name: 'javascripts',
+              tree: [],
+            },
+            {
+              type: 'blob',
+              name: 'index_spec.js',
+              tree: [],
+            },
+          ],
+        },
+      ]);
+    });
+  });
+});