add test action

.github/workflows/cli.yml

@@ -0,0 +1,18 @@
+name: "CodeScanning CLI"
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    # Build the CLI
+    - name: Build CLI
+      run: npm run build-cli
+
+    # Upload an empty SARIF file
+    - name: Upload with CLI
+      run: node cli/code-scanning-cli.js upload --sarif-file src/testdata/empty-sarif.sarif --repository $GITHUB_REPOSITORY --commit $GITHUB_SHA --ref $GITHUB_REF --github-url $GITHUB_API_URL --github-auth ${{ github.token }}

src/testdata/empty-sarif.sarf

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://raw.githubusercontent.com/oasis-tcs/sarif-spec/master/Schemata/sarif-schema-2.1.0.json",
+  "version": "2.1.0",
+  "runs": [
+    {
+      "tool": {
+        "driver": {
+          "name": "LGTM.com",
+          "organization": "Semmle",
+          "version": "1.24.0-SNAPSHOT",
+          "rules": []
+        }
+      },
+      "results": [],
+      "columnKind": "utf16CodeUnits",
+      "properties": {
+        "semmle.formatSpecifier": "2.1.0",
+        "semmle.sourceLanguage": "java"
+      }
+    }
+  ]
+}