Test IDs being added to diff files

spec/frontend/diffs/utils/diff_file_spec.js

 import { prepareRawDiffFile } from '~/diffs/utils/diff_file';
 
-const DIFF_FILES = [
+function getDiffFiles() {
+  return [
     {
-    blob: {
-      id: 'abc',
-      mode: '100644',
-    },
       file_hash: 'ABC', // This file is just a normal file
+      file_identifier_hash: 'ABC1',
+      content_sha: 'C047347',
     },
     {
-    blob: {
-      id: 'bcd',
-      mode: '100644',
-    },
       file_hash: 'DEF', // This file replaces a symlink
+      file_identifier_hash: 'DEF1',
+      content_sha: 'C047347',
       a_mode: '0',
       b_mode: '0755',
     },
     {
-    blob: {
-      id: 'cde',
-      mode: '100644',
-    },
       file_hash: 'DEF', // This symlink is replaced by a file
+      file_identifier_hash: 'DEF2',
+      content_sha: 'C047347',
       a_mode: '120000',
       b_mode: '0',
     },
     {
-    blob: {
-      id: 'def',
-      mode: '100644',
-    },
       file_hash: 'GHI', // This symlink replaces a file
+      file_identifier_hash: 'GHI1',
+      content_sha: 'C047347',
       a_mode: '0',
       b_mode: '120000',
     },
     {
-    blob: {
-      id: 'efg',
-      mode: '100644',
-    },
       file_hash: 'GHI', // This file is replaced by a symlink
+      file_identifier_hash: 'GHI2',
+      content_sha: 'C047347',
       a_mode: '0755',
       b_mode: '0',
     },
-];
-
+  ];
+}
 function makeBrokenSymlinkObject(replaced, wasSymbolic, isSymbolic, wasReal, isReal) {
   return {
     replaced,
@@ -58,6 +49,12 @@ function makeBrokenSymlinkObject(replaced, wasSymbolic, isSymbolic, wasReal, isR
 
 describe('diff_file utilities', () => {
   describe('prepareRawDiffFile', () => {
+    let files;
+
+    beforeEach(() => {
+      files = getDiffFiles();
+    });
+
     it.each`
       fileIndex | description                               | brokenSymlink
       ${0}      | ${'a file that is not symlink-adjacent'}  | ${false}
@@ -69,12 +66,38 @@ describe('diff_file utilities', () => {
       'properly marks $description with the correct .brokenSymlink value',
       ({ fileIndex, brokenSymlink }) => {
         const preppedRaw = prepareRawDiffFile({
-          file: DIFF_FILES[fileIndex],
-          allFiles: DIFF_FILES,
+          file: files[fileIndex],
+          allFiles: files,
         });
 
         expect(preppedRaw.brokenSymlink).toStrictEqual(brokenSymlink);
       },
     );
+
+    it.each`
+      fileIndex | id
+      ${0}      | ${'e075da30-4ec7-4e1c-a505-fe0fb0efe2d8'}
+      ${1}      | ${'5ab05419-123e-4d18-8454-0b8c3d9f3f91'}
+      ${2}      | ${'94eb6bba-575c-4504-bd8e-5d302364d31e'}
+      ${3}      | ${'06d669b2-29b7-4f47-9731-33fc38a8db61'}
+      ${4}      | ${'edd3e8f9-07f9-4647-8171-544c72e5a175'}
+    `('sets the file id properly { id: $id } on normal diff files', ({ fileIndex, id }) => {
+      const preppedFile = prepareRawDiffFile({
+        file: files[fileIndex],
+        allFiles: files,
+      });
+
+      expect(preppedFile.id).toBe(id);
+    });
+
+    it('does not set the `id` property for metadata diff files', () => {
+      const preppedFile = prepareRawDiffFile({
+        file: files[0],
+        allFiles: files,
+        meta: true,
+      });
+
+      expect(preppedFile).not.toHaveProp('id');
+    });
   });
 });