text: #include <stan/math/prim/scal.hpp>
  
  #include <gtest/gtest.h>
  #include <test/unit/util.hpp>
  
  using stan::partials_return_type;
  
  TEST(MetaTraits, PartialsReturnTypeDouble) {
    test::expect_same_type<double, partials_return_type<double>::type>();
  }
  
  TEST(MetaTraits, PartialsReturnTypeFloat) {
    test::expect_same_type<double, partials_return_type<float>::type>();
  }
  
  TEST(MetaTraits, PartialsReturnTypeInt) {
    test::expect_same_type<double, partials_return_type<int>::type>();
  }
  
  TEST(MetaTraits, PartialsReturnTypeScalarTenParams) {
    test::expect_same_type<
        double, partials_return_type<double, int, double, float, float, double,
                                     float, int, double, double>::type>();
  }
  