# vdiffr ignores failures when
#   - VDIFFR_RUN_TESTS is "false" (on Travis CI with older versions and dev
#     version of R)
#   - CI is not set (on CRAN)

if (requireNamespace("vdiffr", quietly = TRUE)) {
    expect_doppelganger <- vdiffr::expect_doppelganger
} else {
    # If vdiffr is not available and visual tests are not explicitly disabled,
    # raise error.
    if (!identical(Sys.getenv("VDIFFR_RUN_TESTS"), "false")) {
        stop("vdiffr is not installed")
    }

    # Otherwise, assign a dummy function
    expect_doppelganger <- function(...) {
        testthat::skip("vdiffr is not installed.")
    }
}