better test for merging of prefs in workspace

Author: KristofferC

test/loading.jl

@@ -1555,8 +1555,9 @@ end
    old_load_path = copy(LOAD_PATH)
    try
        empty!(LOAD_PATH)
-       push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "sub"))
+       push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject"))
        @test Base.get_preferences()["value"] == 1
+       @test Base.get_preferences()["x"] == 1
 
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "sub"))
@@ -1577,6 +1578,8 @@ end
        id_dev = Base.identify_package(id_mypkg, "Devved")
        @test isfile(Base.locate_package(id_dev))
        @test Base.get_preferences()["value"] == 2
+       @test Base.get_preferences()["x"] == 1
+       @test Base.get_preferences()["y"] == 2
 
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "PackageThatIsSub", "test"))
@@ -1590,6 +1593,9 @@ end
        id_dev = Base.identify_package(id_mypkg, "Devved")
        @test isfile(Base.locate_package(id_dev))
        @test Base.get_preferences()["value"] == 3
+       @test Base.get_preferences()["x"] == 1
+       @test Base.get_preferences()["y"] == 2
+       @test Base.get_preferences()["z"] == 3
 
        empty!(LOAD_PATH)
        push!(LOAD_PATH, joinpath(@__DIR__, "project", "SubProject", "test"))

test/project/SubProject/PackageThatIsSub/Project.toml

@@ -11,3 +11,4 @@ MyPkg = "0cafdeb2-d7a2-40d0-8d22-4411fcc2c4ee"
 
 [preferences]
 value = 2
+y = 2

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

@@ -5,3 +5,4 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [preferences]
 value = 3
+z = 3

test/project/SubProject/Project.toml

@@ -10,3 +10,4 @@ Devved2 = "08f74b90-50f5-462f-80b9-a72b1258a17b"
 
 [preferences]
 value = 1
+x = 1