more CI updates

Author: simonbyrne

.github/workflows/UnitTests.yml

@@ -235,10 +235,6 @@ jobs:
 
     runs-on: windows-latest
 
-    env:
-      JULIA_MPI_BINARY: system
-      JULIA_MPIEXEC: "C:\\Program Files\\Microsoft MPI\\Bin\\mpiexec"
-
     steps:
     - name: Cancel Previous Runs
       uses: styfle/[email protected]
@@ -260,18 +256,15 @@ jobs:
       with:
         version: ${{ matrix.julia_version }}
 
-    # https://discourse.julialang.org/t/recommendation-cache-julia-artifacts-in-ci-services/35484
-    - name: Cache artifacts
-      uses: actions/cache@v1
-      env:
-        cache-name: cache-artifacts
-      with:
-        path: ~/.julia/artifacts
-        key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-        restore-keys: |
-          ${{ runner.os }}-test-${{ env.cache-name }}-
-          ${{ runner.os }}-test-
-          ${{ runner.os }}-
+    - uses: julia-actions/cache@v1
+
+    - name: add MPIPreferences, use system
+      shell: julia --color=yes --project=test {0}
+      run: |
+        using Pkg
+        Pkg.develop(path="lib/MPIPreferences")
+        using MPIPreferences
+        MPIPreferences.use_system_binary(export_prefs=true)
 
     - uses: julia-actions/julia-buildpkg@latest
     - uses: julia-actions/julia-runtest@latest
@@ -300,9 +293,6 @@ jobs:
 
     runs-on: ${{ matrix.os }}
 
-    env:
-      JULIA_MPI_BINARY: MPItrampoline_jll
-
     steps:
     - name: Cancel Previous Runs
       uses: styfle/[email protected]
@@ -316,18 +306,15 @@ jobs:
       with:
         version: ${{ matrix.julia_version }}
 
-    # https://discourse.julialang.org/t/recommendation-cache-julia-artifacts-in-ci-services/35484
-    - name: Cache artifacts
-      uses: actions/cache@v1
-      env:
-        cache-name: cache-artifacts
-      with:
-        path: ~/.julia/artifacts
-        key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-        restore-keys: |
-          ${{ runner.os }}-test-${{ env.cache-name }}-
-          ${{ runner.os }}-test-
-          ${{ runner.os }}-
+    - uses: julia-actions/cache@v1
+
+    - name: add MPIPreferences, use system
+      shell: julia --color=yes --project=test {0}
+      run: |
+        using Pkg
+        Pkg.develop(path="lib/MPIPreferences")
+        using MPIPreferences
+        MPIPreferences.use_jll_binary("MPItrampoline", export_prefs=true)
 
     - uses: julia-actions/julia-buildpkg@latest
     - uses: julia-actions/julia-runtest@latest