Add exec tests

test/cli/app_test.rb

@@ -47,6 +47,19 @@ class CliAppTest < CliTestCase
     end
   end
 
+  test "exec" do
+    run_command("exec", "ruby -v").tap do |output|
+      assert_match /ruby -v/, output
+    end
+  end
+
+  test "exec with reuse" do
+    run_command("exec", "--reuse", "ruby -v").tap do |output|
+      assert_match %r[docker ps --filter label=service=app --format \"{{.Names}}\" | sed 's/-/\\n/g' | tail -n 1], output # Get current version
+      assert_match %r[docker exec app-999 ruby -v], output # Get current version
+    end
+  end
+
   private
     def run_command(*command)
       stdouted { Mrsk::Cli::App.start([*command, "-c", "test/fixtures/deploy_with_accessories.yml"]) }