Use SciMLTesting v1.0.0 (run_tests harness)

Replace the hand-written GROUP-dispatch in test/runtests.jl with a single
SciMLTesting.run_tests call. Behavior-equivalent refactor:

- Core (All||Core): the POD / utils / DEIM safetestsets run via the `core` thunk.
- QA: the Quality Assurance / Explicit Imports / JET Static Analysis safetestsets
  run via the `qa` body, which declares the test/qa sub-env. The `qa` kwarg runs
  under both "All" and "QA", matching the original `GROUP=="All" || GROUP=="QA"`.
  activate_group_env(test/qa) develops the repo root + instantiates, equivalent to
  the old Pkg.activate/develop/instantiate.

test/Project.toml: add SciMLTesting (1); drop Pkg (only used by the old harness;
no other test file uses Pkg.). SciMLTesting NOT added to test/qa (stays loaded).

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ChrisRackauckas

test/Project.toml

@@ -1,16 +1,16 @@
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MethodOfLines = "94925ecb-adb7-4558-8ed8-f975c56a0bf4"
-Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
 SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
+SciMLTesting = "09d9d899-5365-40a9-917a-5f67fddea283"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
 LinearAlgebra = "1"
 MethodOfLines = "0.11"
-Pkg = "1.10"
 ModelingToolkit = "11"
 OrdinaryDiffEq = "7"
 SafeTestsets = "0.1"
+SciMLTesting = "1"

test/runtests.jl

@@ -1,32 +1,27 @@
 using SafeTestsets
+using SciMLTesting
 
-const GROUP = get(ENV, "GROUP", "All")
-
-if GROUP == "All" || GROUP == "Core"
-    @safetestset "POD" begin
-        include("DataReduction.jl")
-    end
-    @safetestset "utils" begin
-        include("utils.jl")
-    end
-    @safetestset "DEIM" begin
-        include("deim.jl")
-    end
-end
-
-if GROUP == "All" || GROUP == "QA"
-    using Pkg
-    Pkg.activate(@__DIR__() * "/qa")
-    Pkg.develop(path = dirname(@__DIR__))
-    Pkg.instantiate()
-
-    @safetestset "Quality Assurance" begin
-        include("qa/qa_tests.jl")
-    end
-    @safetestset "Explicit Imports" begin
-        include("qa/explicit_imports_tests.jl")
-    end
-    @safetestset "JET Static Analysis" begin
-        include("qa/jet_tests.jl")
-    end
-end
+run_tests(;
+    core = () -> begin
+        @safetestset "POD" begin
+            include("DataReduction.jl")
+        end
+        @safetestset "utils" begin
+            include("utils.jl")
+        end
+        @safetestset "DEIM" begin
+            include("deim.jl")
+        end
+    end,
+    qa = (; env = joinpath(@__DIR__, "qa"), body = () -> begin
+        @safetestset "Quality Assurance" begin
+            include("qa/qa_tests.jl")
+        end
+        @safetestset "Explicit Imports" begin
+            include("qa/explicit_imports_tests.jl")
+        end
+        @safetestset "JET Static Analysis" begin
+            include("qa/jet_tests.jl")
+        end
+    end),
+)