1 files changed, 164 insertions, 0 deletions
diff --git a/spec/lib/gitlab/changelog/generator_spec.rb b/spec/lib/gitlab/changelog/generator_spec.rb
new file mode 100644
index 00000000000..bc4a7c5dd6b
--- /dev/null
+++ b/spec/lib/gitlab/changelog/generator_spec.rb
@@ -0,0 +1,164 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Changelog::Generator do
+  describe '#add' do
+    let(:project) { build_stubbed(:project) }
+    let(:author) { build_stubbed(:user) }
+    let(:commit) { build_stubbed(:commit) }
+    let(:config) { Gitlab::Changelog::Config.new(project) }
+
+    it 'generates the Markdown for the first release' do
+      release = Gitlab::Changelog::Release.new(
+        version: '1.0.0',
+        date: Time.utc(2021, 1, 5),
+        config: config
+      )
+
+      release.add_entry(
+        title: 'This is a new change',
+        commit: commit,
+        category: 'added',
+        author: author
+      )
+
+      gen = described_class.new('')
+
+      expect(gen.add(release)).to eq(<<~MARKDOWN)
+        ## 1.0.0 (2021-01-05)
+
+        ### added (1 change)
+
+        - [This is a new change](#{commit.to_reference(full: true)})
+      MARKDOWN
+    end
+
+    it 'generates the Markdown for a newer release' do
+      release = Gitlab::Changelog::Release.new(
+        version: '2.0.0',
+        date: Time.utc(2021, 1, 5),
+        config: config
+      )
+
+      release.add_entry(
+        title: 'This is a new change',
+        commit: commit,
+        category: 'added',
+        author: author
+      )
+
+      gen = described_class.new(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+      MARKDOWN
+
+      expect(gen.add(release)).to eq(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 2.0.0 (2021-01-05)
+
+        ### added (1 change)
+
+        - [This is a new change](#{commit.to_reference(full: true)})
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+      MARKDOWN
+    end
+
+    it 'generates the Markdown for a patch release' do
+      release = Gitlab::Changelog::Release.new(
+        version: '1.1.0',
+        date: Time.utc(2021, 1, 5),
+        config: config
+      )
+
+      release.add_entry(
+        title: 'This is a new change',
+        commit: commit,
+        category: 'added',
+        author: author
+      )
+
+      gen = described_class.new(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 2.0.0
+
+        This is another release.
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+      MARKDOWN
+
+      expect(gen.add(release)).to eq(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 2.0.0
+
+        This is another release.
+
+        ## 1.1.0 (2021-01-05)
+
+        ### added (1 change)
+
+        - [This is a new change](#{commit.to_reference(full: true)})
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+      MARKDOWN
+    end
+
+    it 'generates the Markdown for an old release' do
+      release = Gitlab::Changelog::Release.new(
+        version: '0.5.0',
+        date: Time.utc(2021, 1, 5),
+        config: config
+      )
+
+      release.add_entry(
+        title: 'This is a new change',
+        commit: commit,
+        category: 'added',
+        author: author
+      )
+
+      gen = described_class.new(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 2.0.0
+
+        This is another release.
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+      MARKDOWN
+
+      expect(gen.add(release)).to eq(<<~MARKDOWN)
+        This is a changelog file.
+
+        ## 2.0.0
+
+        This is another release.
+
+        ## 1.0.0
+
+        This is the changelog for version 1.0.0.
+
+        ## 0.5.0 (2021-01-05)
+
+        ### added (1 change)
+
+        - [This is a new change](#{commit.to_reference(full: true)})
+      MARKDOWN
+    end
+  end
+end