Allow overriding skipping of tests with VDIFFR_RUN_TESTS

Author: lionel-

NEWS.md

@@ -52,6 +52,11 @@ check how the appearance of your figures changes over time, and to
 manually assess whether changes reflect actual problems in your
 package.
 
+If you need to override the default vdiffr behaviour on CRAN (not
+recommended) or Travis (for example to run the tests in a particular
+builds but not others), set the `VDIFFR_RUN_TESTS` environment
+variable to "true" or "false".
+
 
 ## Features
 

R/testthat-ui.R

@@ -67,6 +67,11 @@
 #' manually assess whether changes reflect actual problems in your
 #' package.
 #'
+#' If you need to override the default vdiffr behaviour on CRAN (not
+#' recommended) or Travis (for example to run the tests in a
+#' particular builds but not others), set the `VDIFFR_RUN_TESTS`
+#' environment variable to "true" or "false".
+#'
 #' @section Debugging:
 #'
 #' It is sometimes difficult to understand the cause of a failure.

R/utils.R

@@ -172,5 +172,18 @@ hash_encode_url <- function(url){
 }
 
 is_ci <- function() {
+  override <- Sys.getenv("VDIFFR_RUN_TESTS")
+  if (nzchar(override)) {
+    override <- parse_expr(toupper(override))
+    if (!is_bool(override)) {
+      abort("`VDIFFR_RUN_TESTS` must be \"true\" or \"false\"")
+    }
+    return(override)
+  }
+
   nzchar(Sys.getenv("CI")) || nzchar(Sys.getenv("NOT_CRAN"))
 }
+
+is_bool <- function(x) {
+  is_logical(x, n = 1) && !is.na(x)
+}

man/expect_doppelganger.Rd

@@ -0,0 +1,10 @@
+context("utils")
+
+test_that("can override is_ci()", {
+  with_override <- function(var) {
+    withr::with_envvar(c(VDIFFR_RUN_TESTS = var, CI = "", NOT_CRAN = ""), is_ci())
+  }
+  expect_true(with_override("true"))
+  expect_false(with_override("false"))
+  expect_error(with_override("falsish"), "must be")
+})