Collapse large diffs by default

When rendering a list of diff files, skip those where the diff is over
10 KB and provide an endpoint to render individually instead.

2 files changed, 72 insertions, 0 deletions

diff --git a/spec/models/merge_request_diff_spec.rb b/spec/models/merge_request_diff_spec.rb
new file mode 100644
index 00000000000..3f5763b6408
--- /dev/null
+++ b/spec/models/merge_request_diff_spec.rb
@@ -0,0 +1,47 @@
+require 'spec_helper'
+
+describe MergeRequestDiff, models: true do
+  describe '#diffs' do
+    let(:mr) { create(:merge_request, :with_diffs) }
+    let(:mr_diff) { mr.merge_request_diff }
+
+    context 'when the :ignore_whitespace_change option is set' do
+      it 'creates a new compare object instead of loading from the DB' do
+        expect(mr_diff).not_to receive(:load_diffs)
+        expect(Gitlab::Git::Compare).to receive(:new).and_call_original
+
+        mr_diff.diffs(ignore_whitespace_change: true)
+      end
+    end
+
+    context 'when the raw diffs are empty' do
+      before { mr_diff.update_attributes(st_diffs: '') }
+
+      it 'returns an empty DiffCollection' do
+        expect(mr_diff.diffs).to be_a(Gitlab::Git::DiffCollection)
+        expect(mr_diff.diffs).to be_empty
+      end
+    end
+
+    context 'when the raw diffs exist' do
+      it 'returns the diffs' do
+        expect(mr_diff.diffs).to be_a(Gitlab::Git::DiffCollection)
+        expect(mr_diff.diffs).not_to be_empty
+      end
+
+      context 'when the :paths option is set' do
+        let(:diffs) { mr_diff.diffs(paths: ['.gitignore', 'files/ruby/popen.rb', 'files/ruby/string.rb']) }
+
+        it 'only returns diffs that match the paths given' do
+          expect(diffs.map(&:new_path)).to contain_exactly('.gitignore', 'files/ruby/popen.rb')
+        end
+
+        it 'uses the diffs from the DB' do
+          expect(mr_diff).to receive(:load_diffs)
+
+          diffs
+        end
+      end
+    end
+  end
+end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index a4b6ff8f8ad..c8ad7ab3e7f 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -116,6 +116,31 @@ describe MergeRequest, models: true do
     end
   end
 
+  describe '#diffs' do
+    let(:merge_request) { build(:merge_request) }
+    let(:options) { { paths: ['a/b', 'b/a', 'c/*'] } }
+
+    context 'when there are MR diffs' do
+      it 'delegates to the MR diffs' do
+        merge_request.merge_request_diff = MergeRequestDiff.new
+
+        expect(merge_request.merge_request_diff).to receive(:diffs).with(options)
+
+        merge_request.diffs(options)
+      end
+    end
+
+    context 'when there are no MR diffs' do
+      it 'delegates to the compare object' do
+        merge_request.compare = double(:compare)
+
+        expect(merge_request.compare).to receive(:diffs).with(options)
+
+        merge_request.diffs(options)
+      end
+    end
+  end
+
   describe "#mr_and_commit_notes" do
     let!(:merge_request) { create(:merge_request) }