1 files changed, 60 insertions, 0 deletions
diff --git a/spec/frontend/diffs/diff_file_spec.js b/spec/frontend/diffs/diff_file_spec.js
new file mode 100644
index 00000000000..5d74760ef66
--- /dev/null
+++ b/spec/frontend/diffs/diff_file_spec.js
@@ -0,0 +1,60 @@
+import { prepareRawDiffFile } from '~/diffs/diff_file';
+
+const DIFF_FILES = [
+  {
+    file_hash: 'ABC', // This file is just a normal file
+  },
+  {
+    file_hash: 'DEF', // This file replaces a symlink
+    a_mode: '0',
+    b_mode: '0755',
+  },
+  {
+    file_hash: 'DEF', // This symlink is replaced by a file
+    a_mode: '120000',
+    b_mode: '0',
+  },
+  {
+    file_hash: 'GHI', // This symlink replaces a file
+    a_mode: '0',
+    b_mode: '120000',
+  },
+  {
+    file_hash: 'GHI', // This file is replaced by a symlink
+    a_mode: '0755',
+    b_mode: '0',
+  },
+];
+
+function makeBrokenSymlinkObject(replaced, wasSymbolic, isSymbolic, wasReal, isReal) {
+  return {
+    replaced,
+    wasSymbolic,
+    isSymbolic,
+    wasReal,
+    isReal,
+  };
+}
+
+describe('diff_file utilities', () => {
+  describe('prepareRawDiffFile', () => {
+    it.each`
+      fileIndex | description                               | brokenSymlink
+      ${0}      | ${'a file that is not symlink-adjacent'}  | ${false}
+      ${1}      | ${'a file that replaces a symlink'}       | ${makeBrokenSymlinkObject(false, false, false, false, true)}
+      ${2}      | ${'a symlink that is replaced by a file'} | ${makeBrokenSymlinkObject(true, true, false, false, false)}
+      ${3}      | ${'a symlink that replaces a file'}       | ${makeBrokenSymlinkObject(false, false, true, false, false)}
+      ${4}      | ${'a file that is replaced by a symlink'} | ${makeBrokenSymlinkObject(true, false, false, true, false)}
+    `(
+      'properly marks $description with the correct .brokenSymlink value',
+      ({ fileIndex, brokenSymlink }) => {
+        const preppedRaw = prepareRawDiffFile({
+          file: DIFF_FILES[fileIndex],
+          allFiles: DIFF_FILES,
+        });
+
+        expect(preppedRaw.brokenSymlink).toStrictEqual(brokenSymlink);
+      },
+    );
+  });
+});