diff --git a/.github/workflows/CI.yml b/.github/workflows/Tests.yml
similarity index 82%
rename from .github/workflows/CI.yml
rename to .github/workflows/Tests.yml
index 46000be..ea43b7f 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/Tests.yml
@@ -1,4 +1,4 @@
-name: CI
+name: Tests
 on:
   push:
     branches:
@@ -13,23 +13,26 @@ concurrency:
 
 jobs:
   test:
-    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }}
+    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.group }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         version:
           - 'lts'
+        group:
+          - spaces
+          - ising
+          - finalize
         os:
           - ubuntu-latest
-        arch:
-          - x64
+          - macOS-latest
+          - windows-latest
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
-          arch: ${{ matrix.arch }}
       - uses: julia-actions/cache@v2
       - uses: julia-actions/julia-buildpkg@latest
       - uses: julia-actions/julia-runtest@latest
diff --git a/test/runtests.jl b/test/runtests.jl
index c96c094..2bc7f62 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -2,8 +2,23 @@ using Test
 using TNRKit
 using TensorKit
 
-using QuadGK
+# check if user supplied args
+pat = r"(?:--group=)(\w+)"
+arg_id = findfirst(contains(pat), ARGS)
+const GROUP = if isnothing(arg_id)
+    uppercase(get(ENV, "GROUP", "ALL"))
+else
+    uppercase(only(match(pat, ARGS[arg_id]).captures))
+end
 
-include("spaces.jl") # do they give spacemismatches?
-include("ising.jl") # do they give the correct results (with the expected accuracy)?
-include("finalize.jl") # do they give the correct results (with the expected accuracy)?
+@time begin
+    if GROUP == "ALL" || GROUP == "SPACES"
+        @time include("spaces.jl") # do they give spacemismatches?
+    end
+    if GROUP == "ALL" || GROUP == "ISING"
+        @time include("ising.jl") # do they give the correct results (with the expected accuracy)?
+    end
+    if GROUP == "ALL" || GROUP == "FINALIZE"
+        @time include("finalize.jl") # do they give the correct results (with the expected accuracy)?
+    end
+end