test preference merging in workspace

Author: KristofferC

test/loading.jl

@@ -1554,6 +1554,10 @@ end
 @testset "workspace loading" begin
    old_load_path = copy(LOAD_PATH)
    try
+       empty!(LOAD_PATH)
+       push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "sub"))
+       @test Base.get_preferences()["value"] == 1
+
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "sub"))
        id = Base.identify_package("Devved")
@@ -1572,6 +1576,7 @@ end
        @test isfile(Base.locate_package(id_mypkg))
        id_dev = Base.identify_package(id_mypkg, "Devved")
        @test isfile(Base.locate_package(id_dev))
+       @test Base.get_preferences()["value"] == 2
 
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "PackageThatIsSub", "test"))
@@ -1584,6 +1589,7 @@ end
        @test isfile(Base.locate_package(id_mypkg))
        id_dev = Base.identify_package(id_mypkg, "Devved")
        @test isfile(Base.locate_package(id_dev))
+       @test Base.get_preferences()["value"] == 3
 
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "test"))

test/project/SubProject/PackageThatIsSub/Project.toml

@@ -8,3 +8,6 @@ projects = ["test"]
 [deps]
 Devved2 = "08f74b90-50f5-462f-80b9-a72b1258a17b"
 MyPkg = "0cafdeb2-d7a2-40d0-8d22-4411fcc2c4ee"
+
+[preferences]
+value = 2

test/project/SubProject/PackageThatIsSub/test/Project.toml

@@ -2,3 +2,6 @@
 MyPkg = "0cafdeb2-d7a2-40d0-8d22-4411fcc2c4ee"
 PackageThatIsSub = "1efb588c-9412-4e40-90a4-710420bd84aa"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[preferences]
+value = 3

test/project/SubProject/Project.toml

@@ -7,3 +7,6 @@ projects = ["sub", "PackageThatIsSub", "test"]
 [deps]
 Devved = "cbce3a6e-7a3d-4e84-8e6d-b87208df7599"
 Devved2 = "08f74b90-50f5-462f-80b9-a72b1258a17b"
+
+[preferences]
+value = 1

test/project/SubProject/sub/Project.toml

@@ -1,2 +1,3 @@
 [deps]
 Devved = "cbce3a6e-7a3d-4e84-8e6d-b87208df7599"
+MyPkg = "0cafdeb2-d7a2-40d0-8d22-4411fcc2c4ee"