1 files changed, 54 insertions, 0 deletions
diff --git a/spec/finders/repositories/changelog_tag_finder_spec.rb b/spec/finders/repositories/changelog_tag_finder_spec.rb
new file mode 100644
index 00000000000..cd79beb3e9e
--- /dev/null
+++ b/spec/finders/repositories/changelog_tag_finder_spec.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Repositories::ChangelogTagFinder do
+  let(:project) { build_stubbed(:project) }
+  let(:finder) { described_class.new(project) }
+
+  describe '#execute' do
+    context 'when the regular expression is invalid' do
+      it 'raises Gitlab::Changelog::Error' do
+        expect { described_class.new(project, regex: 'foo+*').execute('1.2.3') }
+          .to raise_error(Gitlab::Changelog::Error)
+      end
+    end
+
+    context 'when there is a previous tag' do
+      it 'returns the previous tag' do
+        tag1 = double(:tag1, name: 'v1.0.0')
+        tag2 = double(:tag2, name: 'v1.1.0')
+        tag3 = double(:tag3, name: 'v2.0.0')
+        tag4 = double(:tag4, name: '0.9.0')
+        tag5 = double(:tag5, name: 'v0.8.0-pre1')
+        tag6 = double(:tag6, name: 'v0.7.0')
+        tag7 = double(:tag7, name: '0.5.0+42.ee.0')
+
+        allow(project.repository)
+          .to receive(:tags)
+          .and_return([tag1, tag3, tag2, tag4, tag5, tag6, tag7])
+
+        expect(finder.execute('2.1.0')).to eq(tag3)
+        expect(finder.execute('2.0.0')).to eq(tag2)
+        expect(finder.execute('1.5.0')).to eq(tag2)
+        expect(finder.execute('1.0.1')).to eq(tag1)
+        expect(finder.execute('1.0.0')).to eq(tag4)
+        expect(finder.execute('0.9.0')).to eq(tag6)
+        expect(finder.execute('0.6.0')).to eq(tag7)
+      end
+    end
+
+    context 'when there is no previous tag' do
+      it 'returns nil' do
+        tag1 = double(:tag1, name: 'v1.0.0')
+        tag2 = double(:tag2, name: 'v1.1.0')
+
+        allow(project.repository)
+          .to receive(:tags)
+          .and_return([tag1, tag2])
+
+        expect(finder.execute('1.0.0')).to be_nil
+      end
+    end
+  end
+end