Add a view test for showing source commits

spec/views/projects/merge_requests/_commits.html.haml_spec.rb

+require 'spec_helper'
+
+describe 'projects/merge_requests/show/_commits.html.haml' do
+  include Devise::Test::ControllerHelpers
+
+  let(:user) { create(:user) }
+  let(:target_project) { create(:project) }
+
+  let(:source_project) do
+    create(:project, forked_from_project: target_project)
+  end
+
+  let(:merge_request) do
+    create(:merge_request, :simple,
+      source_project: source_project,
+      target_project: target_project,
+      author: user)
+  end
+
+  before do
+    controller.prepend_view_path('app/views/projects')
+
+    assign(:merge_request, merge_request)
+    assign(:commits, merge_request.commits)
+  end
+
+  it 'shows commits from source project' do
+    render
+
+    commit = source_project.commit(merge_request.source_branch)
+    href = namespace_project_commit_path(
+      source_project.namespace,
+      source_project,
+      commit)
+
+    expect(rendered).to have_link(Commit.truncate_sha(commit.sha), href: href)
+  end
+end