GITHUB: Add test job

.github/workflows/build.yml

@@ -19,6 +19,12 @@ jobs:
       - name: Build
         run: go build -o fireball ./cmd
 
+      - name: Cache fireball
+        uses: actions/cache/save@v3
+        with:
+          path: fireball
+          key: ${{ runner.os }}-${{ hashFiles('fireball') }}
+
       - name: Set up Node
         uses: actions/setup-node@v3
         with:
@@ -40,4 +46,27 @@ jobs:
         with:
           path: |
             fireball
-            vscode/*.vsix
+            vscode/*.vsix
+
+  test:
+    runs-on: ubuntu-latest
+    needs: "build"
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v3
+
+      - name: Get fireball from cache
+        uses: actions/cache/restore@v3
+        with:
+          path: fireball
+          key: ${{ runner.os }}-${{ hashFiles('fireball') }}
+
+      - name: Install LLVM
+        uses: KyleMayes/install-llvm-action@v1
+        with:
+          version: "17.0.2"
+
+      - name: Run tests
+        run: |
+          cd tests
+          ../fireball test