fixup! Add support for DistributedNext

Author: JamesWrigley

test/preferences.jl

@@ -0,0 +1,21 @@
+import Preferences: load_preference, set_preferences!
+
+@testset "Preferences" begin
+    cmd = `$(Base.julia_cmd()) --startup-file=no --project -E 'using Dagger; parentmodule(Dagger.myid)'`
+
+    try
+        # Disabling the precompilation workload shaves off over half the time
+        # this test takes.
+        set_preferences!(Dagger, "precompile_workload" => false; force=true)
+
+        cd(dirname(Base.active_project())) do
+            Dagger.set_distributed_package!("Distributed")
+            @test readchomp(cmd) == "Distributed"
+
+            Dagger.set_distributed_package!("DistributedNext")
+            @test readchomp(cmd) == "DistributedNext"
+        end
+    finally
+        set_preferences!(Dagger, "precompile_workload" => false; force=true)
+    end
+end