1 files changed, 58 insertions, 0 deletions
diff --git a/spec/lib/gitlab/gitaly_client/commit_spec.rb b/spec/lib/gitlab/gitaly_client/commit_spec.rb
new file mode 100644
index 00000000000..4d812b876e4
--- /dev/null
+++ b/spec/lib/gitlab/gitaly_client/commit_spec.rb
@@ -0,0 +1,58 @@
+require 'spec_helper'
+
+describe Gitlab::GitalyClient::Commit do
+  describe '.diff_from_parent' do
+    let(:diff_stub) { double('Gitaly::Diff::Stub') }
+    let(:project) { create(:project) }
+    let(:repository_message) { Gitaly::Repository.new(path: project.repository.path) }
+    let(:commit) { project.commit('913c66a37b4a45b9769037c55c2d238bd0942d2e') }
+
+    before do
+      allow(Gitaly::Diff::Stub).to receive(:new).and_return(diff_stub)
+      allow(diff_stub).to receive(:commit_diff).and_return([])
+    end
+
+    context 'when a commit has a parent' do
+      it 'sends an RPC request with the parent ID as left commit' do
+        request = Gitaly::CommitDiffRequest.new(
+          repository: repository_message,
+          left_commit_id: 'cfe32cf61b73a0d5e9f13e774abde7ff789b1660',
+          right_commit_id: commit.id,
+        )
+
+        expect(diff_stub).to receive(:commit_diff).with(request)
+
+        described_class.diff_from_parent(commit)
+      end
+    end
+
+    context 'when a commit does not have a parent' do
+      it 'sends an RPC request with empty tree ref as left commit' do
+        initial_commit = project.commit('1a0b36b3cdad1d2ee32457c102a8c0b7056fa863')
+        request        = Gitaly::CommitDiffRequest.new(
+          repository: repository_message,
+          left_commit_id: '4b825dc642cb6eb9a060e54bf8d69288fbee4904',
+          right_commit_id: initial_commit.id,
+        )
+
+        expect(diff_stub).to receive(:commit_diff).with(request)
+
+        described_class.diff_from_parent(initial_commit)
+      end
+    end
+
+    it 'returns a Gitlab::Git::DiffCollection' do
+      ret = described_class.diff_from_parent(commit)
+
+      expect(ret).to be_kind_of(Gitlab::Git::DiffCollection)
+    end
+
+    it 'passes options to Gitlab::Git::DiffCollection' do
+      options = { max_files: 31, max_lines: 13 }
+
+      expect(Gitlab::Git::DiffCollection).to receive(:new).with([], options)
+
+      described_class.diff_from_parent(commit, options)
+    end
+  end
+end