Update maven.yml

Author: wjglerum

.github/workflows/maven.yml

@@ -9,23 +9,26 @@ on:
   pull_request:
     branches: [ main ]
   workflow_dispatch:
+  
+env:
+  EXERCISES_DIRECTORY: ./code
 
 jobs:
-  get-exercises:
+  list-exercises:
     runs-on: ubuntu-latest
     outputs:
-      matrix: ${{steps.list_dirs.outputs.matrix}}
+      exercises: ${{steps.list.outputs.exercises}}
     steps:
       - uses: actions/checkout@v2
-      - id: list_dirs
-        run: echo "::set-output name=matrix::$(ls code | jq -cnR '[inputs | select(length>0)]')"
+      - id: list
+        run: echo "::set-output name=exercises::$(ls $EXERCISES_DIRECTORY | jq -cnR '[inputs | select(length>0)]')"
   build:
     runs-on: ubuntu-latest
-    needs: get-exercises
+    needs: list-exercises
     strategy:
       fail-fast: false
       matrix:
-        subdir: ${{fromJson(needs.get-exercises.outputs.matrix)}}    
+        exercise: ${{fromJson(needs.list-exercises.outputs.exercises)}}    
     steps:
     - uses: actions/checkout@v3
     - name: Set up JDK
@@ -35,4 +38,5 @@ jobs:
         distribution: 'temurin'
         cache: maven
     - name: Test with Maven
-      run: mvn -B verify --file code/${{matrix.subdir}}/pom.xml
+      run: mvn -B verify --file pom.xml
+      working-directory: $EXERCISES_DIRECTORY/${{matrix.exercise}}