Add test with locally-defined S4 methods as globals [#615]

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: future
-Version: 1.25.0-9009
+Version: 1.25.0-9010
 Title: Unified Parallel and Distributed Processing in R for Everyone
 Imports:
     digest,
@@ -10,6 +10,7 @@ Imports:
     tools,
     utils
 Suggests:
+    methods,
     RhpcBLASctl,
     R.rsp,
     markdown

NEWS

@@ -1,7 +1,7 @@
 Package: future
 ===============
 
-Version: 1.25.0-9009 [2022-05-03]
+Version: 1.25.0-9010 [2022-05-06]
 
 SIGNIFICANT CHANGES:
 

tests/globals,S4methods.R

@@ -0,0 +1,38 @@
+source("incl/start.R")
+library(methods)
+
+keepWhere <- getOption("future.globals.keepWhere")
+
+message("*** Globals - S4 methods ...")
+
+setGeneric("my_fcn", function(x) {
+    standardGeneric("my_fcn")
+})
+
+setMethod("my_fcn", methods::signature(x = "numeric"), function(x) {
+  x^2
+})
+
+truth <- my_fcn(3)
+
+for (strategy in supportedStrategies()) {
+  message("Type of future: ", strategy)
+  plan(strategy)
+
+  ## FIXME: https://github.com/HenrikBengtsson/future/issues/615
+  if (strategy %in% c("sequential", "multicore")) {
+    options(future.globals.keepWhere = TRUE)
+  }
+
+  f <- future({ my_fcn(3) })
+  v <- value(f)
+  print(v)
+  stopifnot(v == truth)
+
+  ## Make sure to reset option, if changed
+  options(future.globals.keepWhere = keepWhere)
+}
+
+message("*** Globals - S4 methods ... DONE")
+
+source("incl/end.R")