Extend cache action (#4)

* Extend cache action

* Also test on Windows and macOS

* Fix a problem with setting output on Windows

* Use echo after set-output

* Generate key only once

* Fix non-matching name (should fail but doesn't weirdly)

* Update action.yml

Co-authored-by: Sascha Mann <git@mail.saschamann.eu>

* Update action.yml

Co-authored-by: Sascha Mann <git@mail.saschamann.eu>

Co-authored-by: Sascha Mann <git@mail.saschamann.eu>

.github/workflows/CI.yml

@@ -11,27 +11,34 @@ on:
       - 'action.yml'
 
 jobs:
-  test-save:
+  generate-key:
     runs-on: ubuntu-latest
     outputs:
       cache-name: ${{ steps.name.outputs.cache-name }}
     steps:
-    - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
     - name: Generate random file
       shell: 'julia --color=yes {0}'
       run: 'write("random.txt", string(rand(10)))'
+    - name: Set cache-name as output
+      id: name
+      run: echo "::set-output name=cache-name::$(echo $CACHE_NAME)"
+      env:
+        CACHE_NAME: ${{ hashFiles('random.txt') }}
+
+  test-save:
+    needs: generate-key
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
     - name: Save cache
       id: cache
       uses: ./
       with:
-        cache-name: ${{ hashFiles('random.txt') }}
-    - name: Set cache-name as output
-      id: name
-      run: |
-        echo "Setting outputs.cache-name to \"$CACHE_NAME\""
-        echo "::set-output name=cache-name::$CACHE_NAME"
-      env:
-        CACHE_NAME: ${{ hashFiles('random.txt') }}
+        cache-name: ${{ needs.generate-key.outputs.cache-name }}
     - name: Check no artifacts dir
       shell: 'julia --color=yes {0}'
       run: |
@@ -42,15 +49,19 @@ jobs:
       run: 'using Pkg; Pkg.add("pandoc_jll")'
 
   test-restore:
-    needs: test-save
-    runs-on: ubuntu-latest
+    needs: [generate-key, test-save]
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
     - name: Restore cache
       id: cache
       uses: ./
       with:
-        cache-name: ${{ needs.test-save.outputs.cache-name }}
+        cache-name: ${{ needs.generate-key.outputs.cache-name }}
     - name: Test cache-hit output
       shell: 'julia --color=yes {0}'
       run: |