if(require("suppdata") & require("testthat")){
    
    context("PeerJ and PeerJ Preprints")

    test_that("PeerJ Preprints works with numeric SI", {    
        skip_on_cran()
        expect_true(file.exists(suppdata("10.7287/peerj.preprints.26561v1", si = 1)))
    })

    test_that("PeerJ Preprints works with character SI", {    
        skip_on_cran()
        expect_true(file.exists(suppdata("10.7287/peerj.preprints.26561v1", si = "supp-2")))
    })

    test_that("PeerJ works with numeric SI", {    
        skip_on_cran()
        expect_true(file.exists(suppdata("10.7717/peerj.3006", si = 1)))
    })

    test_that("PeerJ works with character SI", {    
        skip_on_cran()
        expect_true(file.exists(suppdata("10.7717/peerj.3006", si = "supp-2")))
    })

    test_that("PeerJ with multiple DOIs work using numeric SI", {    
        skip_on_cran()
        expect_true(all(file.exists(suppdata(c("10.7287/peerj.preprints.26561v1",
                                               "10.7717/peerj.3006"),
                                             si = 1))))
    })

    test_that("PeerJ with multiple DOIs work using character SI", {    
        skip_on_cran()
        expect_true(all(file.exists(suppdata(c("10.7287/peerj.preprints.26561v1",
                                               "10.7717/peerj.3006"),
                                             si = "supp-2"))))
    })

    test_that("Accessing specific SI from PeerJ has correct suffix for file", {    
        skip_on_cran()
        expect_equal(attr(suppdata("10.7717/peerj.3006", si = 1), which = "suffix"), "docx")
    })

    test_that("Accessing specific SI from PeerJ Preprints has correct suffix for file", {    
        skip_on_cran()
        expect_equal(attr(suppdata("10.7287/peerj.preprints.26561", si = 1), which = "suffix"), "csv")
    })

}