Add CI for Sum tests

.gitea/workflows/sum.yml

@@ -0,0 +1,25 @@
+name: Sum Tests
+
+on:
+  push:
+    paths:
+      - 'java/sum/**'
+      - 'java/base/**'
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Compile Java
+        run: |
+          mkdir -p out
+          javac -d out $(find java -name "*.java")
+      
+      - name: Run Sum tests
+        run: |
+          java -ea -cp out sum.SumTest Base 3233 3435 3637 3839 4142 4749