void hasPlugin(String alias, @DelegatesTo(strategy = Closure.DELEGATE_FIRST, value = PluginSpec) Closure<Void> spec) {
        assert model.hasPlugin(alias)
        def plugin = model.getPlugin(alias)
        assert plugin != null : "Expected a plugin with alias '$alias' but it wasn't found"
        def pluginSpec = new PluginSpec(plugin)
        spec.delegate = pluginSpec
        spec.resolveStrategy = Closure.DELEGATE_FIRST
        spec()
    }