commit signature with spec

app/models/commit.rb

@@ -237,7 +237,7 @@ class Commit
   def signature
     return @signature if defined?(@signature)
 
-    sig, signed = @raw.extract_signature(project.repository.raw_repository)
+    sig, signed = @raw.signature(project.repository)
     if sig && signed
       GPGME::Crypto.new.verify(sig, signed_text: signed) do |sign|
         @signature = sign

lib/gitlab/git/commit.rb

@@ -319,7 +319,12 @@ module Gitlab
         end
       end
 
-      def extract_signature(repo)
+      # Get the gpg signature of this commit.
+      #
+      # Ex.
+      #   commit.signature(repo)
+      #
+      def signature(repo)
         Rugged::Commit.extract_signature(repo.rugged, sha)
       end
 

spec/models/commit_spec.rb

@@ -414,4 +414,44 @@ eos
       expect(described_class.valid_hash?('a' * 41)).to be false
     end
   end
+
+  describe '#signature' do
+    it 'returns nil if the commit is not signed' do
+      expect(commit.signature).to be_nil
+    end
+
+    context 'signed commit', :gpg do
+      it 'returns a valid signature if the public key is known' do
+        GPGME::Key.import(GpgHelpers.public_key)
+
+        raw_commit = double(:raw_commit, signature: [
+          GpgHelpers.signed_commit_signature,
+          GpgHelpers.signed_commit_base_data
+        ])
+        allow(raw_commit).to receive :save!
+
+        commit = create :commit,
+          git_commit: raw_commit,
+          project: project
+
+        expect(commit.signature).to be_a GPGME::Signature
+        expect(commit.signature.valid?).to be_truthy
+      end
+
+      it 'returns an invalid signature if the public commit is unknown', :gpg do
+        raw_commit = double(:raw_commit, signature: [
+          GpgHelpers.signed_commit_signature,
+          GpgHelpers.signed_commit_base_data
+        ])
+        allow(raw_commit).to receive :save!
+
+        commit = create :commit,
+          git_commit: raw_commit,
+          project: project
+
+        expect(commit.signature).to be_a GPGME::Signature
+        expect(commit.signature.valid?).to be_falsey
+      end
+    end
+  end
 end

spec/spec_helper.rb

@@ -141,6 +141,18 @@ RSpec.configure do |config|
   config.around(:each, :postgresql) do |example|
     example.run if Gitlab::Database.postgresql?
   end
+
+  config.around(:each, :gpg) do |example|
+    Dir.mktmpdir do |dir|
+      original_dir = GPGME::Engine.dirinfo('homedir')
+
+      GPGME::Engine.home_dir = dir
+
+      example.run
+
+      GPGME::Engine.home_dir = original_dir
+    end
+  end
 end
 
 FactoryGirl::SyntaxRunner.class_eval do