Default to SSH clone URI when private_key is set

Fixes jtarchie#205.

assets/lib/commands/in.rb

@@ -79,7 +79,9 @@ def pr
     end
 
     def uri
-      input.source.uri || "https://github.com/#{input.source.repo}"
+      return input.source.uri if input.source.uri
+      return "[email protected]:#{input.source.repo}.git" if input.source.private_key
+      return "https://github.com/#{input.source.repo}"
     end
 
     def ref

spec/commands/in_spec.rb

@@ -16,11 +16,15 @@ def git_uri
 
   let(:dest_dir) { Dir.mktmpdir }
 
-  def get(payload)
+  def command(payload)
     payload['source']['skip_ssl_verification'] = true
     Input.instance(payload: payload)
-    command = Commands::In.new(destination: dest_dir)
-    command.output
+
+    Commands::In.new(destination: dest_dir)
+  end
+
+  def get(payload)
+    command(payload).output
   end
 
   def stub_json(uri, body)
@@ -158,6 +162,20 @@ def dest_dir
       end
     end
 
+    context 'when an SSH key is specified' do
+      it 'defaults to an SSH clone URI' do
+        cmd = command('version' => { 'ref' => @ref, 'pr' => '1' }, 'source' => { 'private_key' => '-----BEGIN', 'repo' => 'jtarchie/test' })
+        expect(cmd.send(:uri)).to eq '[email protected]:jtarchie/test.git'
+      end
+    end
+
+    context 'when an SSH key is not specified' do
+      it 'defaults to an HTTPS clone URI' do
+        cmd = command('version' => { 'ref' => @ref, 'pr' => '1' }, 'source' => { 'repo' => 'jtarchie/test' })
+        expect(cmd.send(:uri)).to eq 'https://github.com/jtarchie/test'
+      end
+    end
+
     context 'when the git clone fails' do
       it 'provides a helpful erorr message' do
         stub_json('https://api.github.com:443/repos/jtarchie/test/pulls/1', html_url: 'http://example.com', number: 1, head: { ref: 'foo' }, base: { ref: 'master', user: { login: 'jtarchie' } }, user: { login: 'jtarchie-contributor' })