1 files changed, 15 insertions, 4 deletions
diff --git a/spec/lib/gitlab/background_migration/set_merge_request_diff_files_count_spec.rb b/spec/lib/gitlab/background_migration/set_merge_request_diff_files_count_spec.rb
index 6e9f51f510a..f23518625e4 100644
--- a/spec/lib/gitlab/background_migration/set_merge_request_diff_files_count_spec.rb
+++ b/spec/lib/gitlab/background_migration/set_merge_request_diff_files_count_spec.rb
@@ -13,11 +13,11 @@ RSpec.describe Gitlab::BackgroundMigration::SetMergeRequestDiffFilesCount, schem
   let(:project) { projects.create!(namespace_id: namespace.id) }
   let(:merge_request) { merge_requests.create!(source_branch: 'x', target_branch: 'master', target_project_id: project.id) }
 
-  it 'fills the files_count column' do
-    empty_diff = merge_request_diffs.create!(merge_request_id: merge_request.id)
-    filled_diff = merge_request_diffs.create!(merge_request_id: merge_request.id)
+  let!(:empty_diff) { merge_request_diffs.create!(merge_request_id: merge_request.id) }
+  let!(:filled_diff) { merge_request_diffs.create!(merge_request_id: merge_request.id) }
 
-    3.times do |n|
+  let!(:filled_diff_files) do
+    1.upto(3).map do |n|
       merge_request_diff_files.create!(
         merge_request_diff_id: filled_diff.id,
         relative_order: n,
@@ -31,10 +31,21 @@ RSpec.describe Gitlab::BackgroundMigration::SetMergeRequestDiffFilesCount, schem
         new_path: ''
       )
     end
+  end
 
+  it 'fills the files_count column' do
     described_class.new.perform(empty_diff.id, filled_diff.id)
 
     expect(empty_diff.reload.files_count).to eq(0)
     expect(filled_diff.reload.files_count).to eq(3)
   end
+
+  it 'uses the sentinel value if the actual count is too high' do
+    stub_const("#{described_class}::FILES_COUNT_SENTINEL", filled_diff_files.size - 1)
+
+    described_class.new.perform(empty_diff.id, filled_diff.id)
+
+    expect(empty_diff.reload.files_count).to eq(0)
+    expect(filled_diff.reload.files_count).to eq(described_class::FILES_COUNT_SENTINEL)
+  end
 end