# Does TestItems work in julia 1.12 using new package workspace feature

**URL:** <https://discourse.julialang.org/t/does-testitems-work-in-julia-1-12-using-new-package-workspace-feature/133722>\
**Category:** VS Code\
**Created:** [November 6, 2025, 11:59pm UTC](https://discourse.julialang.org/t/does-testitems-work-in-julia-1-12-using-new-package-workspace-feature/133722 "2025-11-06T23:59:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![brianguenter](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/brianguenter/32/29519_2.png) [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Post date:** [November 6, 2025, 11:59pm UTC](https://discourse.julialang.org/t/does-testitems-work-in-julia-1-12-using-new-package-workspace-feature/133722/1 "2025-11-06T23:59:32Z")

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I just switched one of my packages to use the new workspace system, where the test directory has its own Project.toml.

Tests run correctly from the REPL but when I try to use the VSCode testing framework none of the tests run. Instead I get this error message:

```julia
[ Info: Julia test item process launching
  Activating project at `c:\Users\seatt\source\OpticSim.jl`
ERROR: MethodError: no method matching prune_manifest(::Pkg.Types.Manifest, ::Vector{Base.UUID})
The function `prune_manifest` exists, but no method is defined for this combination of argument types.

Closest candidates are:
  prune_manifest(::Pkg.Types.Manifest, !Matched::Set{Base.UUID})
   @ Pkg C:\Users\seatt\.julia\juliaup\julia-1.12.1+0.x64.w64.mingw32\share\julia\stdlib\v1.12\Pkg\src\Operations.jl:1214
  prune_manifest(!Matched::Pkg.Types.EnvCache)
   @ Pkg C:\Users\seatt\.julia\juliaup\julia-1.12.1+0.x64.w64.mingw32\share\julia\stdlib\v1.12\Pkg\src\Operations.jl:1193

Stacktrace:
 [1] activate(pkg::String; allow_reresolve::Bool)
   @ TestItemServer.TestEnv c:\Users\seatt\.vscode\extensions\julialang.language-julia-1.149.2\scripts\packages\TestItemControllers\packages\TestEnv\src\julia-1.11\activate_set.jl:40
 [2] activate
   @ c:\Users\seatt\.vscode\extensions\julialang.language-julia-1.149.2\scripts\packages\TestItemControllers\packages\TestEnv\src\julia-1.11\activate_set.jl:9 [inlined]
 [3] activate_env_request(params::TestItemServer.TestItemServerProtocol.ActivateEnvParams, state::TestItemServer.TestProcessState{var"#2#3"}, token::TestItemServer.CancellationTokens.CancellationToken)
   @ TestItemServer c:\Users\seatt\.vscode\extensions\julialang.language-julia-1.149.2\scripts\packages\TestItemControllers\testprocess\TestItemServer\src\TestItemServer.jl:551
 [4] dispatch_msg(x::TestItemServer.JSONRPC.JSONRPCEndpoint{Base.PipeEndpoint, Base.PipeEndpoint}, msg::TestItemServer.JSONRPC.Request, context::TestItemServer.TestProcessState{var"#2#3"})
   @ TestItemServer c:\Users\seatt\.vscode\extensions\julialang.language-julia-1.149.2\scripts\packages\TestItemControllers\packages\JSONRPC\src\typed.jl:114
 [5] (::TestItemServer.var"#serve##2#serve##3"{TestItemServer.TestProcessState{var"#2#3"}, TestItemServer.JSONRPC.JSONRPCEndpoint{Base.PipeEndpoint, Base.PipeEndpoint}, TestItemServer.JSONRPC.Request})()
   @ TestItemServer c:\Users\seatt\.vscode\extensions\julialang.language-julia-1.149.2\scripts\packages\TestItemControllers\testprocess\TestItemServer\src\TestItemServer.jl:710

```

Does the VSCode test framework not work in 1.12 with workspaces?

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<div class="post-metadata">

**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [November 7, 2025, 5:44am UTC](https://discourse.julialang.org/t/does-testitems-work-in-julia-1-12-using-new-package-workspace-feature/133722/2 "2025-11-07T05:44:21Z")

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Not a direct answer to your question but which version of the extension are you on? There was a new pre release version released yesterday which fixes a bunch of 1.12 specific issues.

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<div class="post-metadata">

**Author:** ![visr](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/visr/32/17204_2.png) [@visr](https://discourse.julialang.org/u/visr)\
**Post date:** [November 7, 2025, 12:49pm UTC](https://discourse.julialang.org/t/does-testitems-work-in-julia-1-12-using-new-package-workspace-feature/133722/3 "2025-11-07T12:49:56Z")

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Yes this issue was [Cannot run 1.12 testitems; `prune_manifest` MethodError · Issue #3885 · julia-vscode/julia-vscode](https://github.com/julia-vscode/julia-vscode/issues/3885), which has been fixed on pre-release v1.157.0.