if(require("suppdata") & require("testthat")){
    
    context("MDPI")

    test_that("MDPI journal works with numeric SI", {    
        skip_on_cran()
        expect_true(file.exists(suppdata("10.3390/cosmetics2020066", si = 2)))
    })

    test_that("MDPI fails with non-existing SI", {    
        skip_on_cran()
        expect_error(suppdata("10.3390/arts8020048", si = 3), "No SI with id")
    })

    test_that("MDPI fails with character SI", {    
        skip_on_cran()
        expect_error(suppdata("10.3390/arts8020048", si = "s1"), "numeric SI")
    })

    test_that("MDPI with multiple DOIs work using numeric SI", {    
        skip_on_cran()
        expect_true(all(file.exists(suppdata(c("10.3390/arts8020048",
                                               "10.3390/rs9101025"),
                                             si = 1))))
    })

    test_that("Accessing single SI from MDPI has correct suffix for pdf file", {    
        skip_on_cran()
        expect_equal(attr(suppdata("10.3390/rs9101025", si = 1), which = "suffix"), "pdf")
    })

    test_that("Accessing single SI from MDPI has correct suffix for zip file", {    
        skip_on_cran()
        expect_equal(attr(suppdata("10.3390/arts8020048", si = 1), which = "suffix"), "zip")
    })

}