improve error handling

src/index.js

@@ -61,13 +61,20 @@ async function invoke(Cls) {
     core.setFailed(reason);
   });
 
-  if (!(Cls.prototype instanceof BaseAction)) {
-    throw new Error("Action class must extend BaseAction");
-  }
+  let obj;
+  let rendered;
+  try {
+    if (!(Cls.prototype instanceof BaseAction)) {
+      throw new Error("Action class must extend BaseAction");
+    }
 
-  const obj = new Cls();
-  const rendered = await obj.render();
-  if (rendered == null) {
+    obj = new Cls();
+    rendered = await obj.render();
+    if (rendered == null) {
+      return;
+    }
+  } catch (e) {
+    core.setFailed(e.message);
     return;
   }
 

src/index.spec.js

@@ -42,19 +42,19 @@ describe("invoke", function () {
   it("throws an exception if class is not instance of BaseAction", async function () {
     class BadTestAction {}
 
-    await assert.rejects(invoke(BadTestAction), {
-      name: "Error",
-      message: "Action class must extend BaseAction",
-    });
+    const setFailed = sinon.spy(core, "setFailed");
+    await invoke(BadTestAction);
+    assert(setFailed.calledOnce);
+    assert(setFailed.calledWith("Action class must extend BaseAction"));
   });
 
   it("throws an exception if class has no render() function", async function () {
     class BadTestAction extends BaseAction {}
 
-    await assert.rejects(invoke(BadTestAction), {
-      name: "Error",
-      message: "render not implemented",
-    });
+    const setFailed = sinon.spy(core, "setFailed");
+    await invoke(BadTestAction);
+    assert(setFailed.calledOnce);
+    assert(setFailed.calledWith("render not implemented"));
   });
 
   it("fails the build if writeBadge throws an error", async function () {