Add test for throwing route handler

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

src/main/router.test.ts

@@ -13,6 +13,7 @@ import type { AsyncFnMock } from "@async-fn/jest";
 import asyncFn from "@async-fn/jest";
 import parseRequestInjectable from "./router/parse-request.injectable";
 import { contentTypes } from "./router-content-types";
+import mockFs from "mock-fs";
 
 describe("router", () => {
   let router: Router;
@@ -23,6 +24,8 @@ describe("router", () => {
 
     const di = getDiForUnitTesting({ doGeneralOverrides: true });
 
+    mockFs();
+
     di.override(parseRequestInjectable, () => () => Promise.resolve({ payload: "some-payload" }));
 
     await di.runSetups();
@@ -44,6 +47,10 @@ describe("router", () => {
     router = di.inject(routerInjectable);
   });
 
+  afterEach(() => {
+    mockFs.restore();
+  });
+
   describe("when navigating to the route", () => {
     let actualPromise: Promise<boolean>;
     let clusterStub: Cluster;
@@ -97,6 +104,46 @@ describe("router", () => {
       expect(responseStub.end).toHaveBeenCalledWith('{"some":"object"}');
     });
 
+    describe("when handler resolves without any result", () => {
+      beforeEach(async () => {
+        await routeHandlerMock.resolve(undefined);
+
+        await actualPromise;
+      });
+
+      it("resolves as plain text", () => {
+        expect(responseStub.setHeader.mock.calls).toEqual([["Content-Type", "text/plain"]]);
+      });
+
+      it("resolves with status code for no content", async () => {
+        expect(responseStub.statusCode).toBe(204);
+      });
+
+      it("resolves without content", async () => {
+        expect(responseStub.end.mock.calls).toEqual([[]]);
+      });
+    });
+
+    describe("when handler rejects", () => {
+      beforeEach(async () => {
+        await routeHandlerMock.reject(new Error("some-error"));
+
+        await actualPromise;
+      });
+
+      it("resolves as plain text", () => {
+        expect(responseStub.setHeader.mock.calls).toEqual([["Content-Type", "text/plain"]]);
+      });
+
+      it('resolves with "422" status code', () => {
+        expect(responseStub.statusCode).toBe(422);
+      });
+
+      it("resolves with error", () => {
+        expect(responseStub.end).toHaveBeenCalledWith("Error: some-error");
+      });
+    });
+
     [
       { contentType: "text/plain", contentTypeObject: contentTypes.txt },
       { contentType: "application/json", contentTypeObject: contentTypes.json },
@@ -164,7 +211,7 @@ describe("router", () => {
 
         await actualPromise;
 
-        expect(responseStub.end).toHaveBeenCalledWith(undefined);
+        expect(responseStub.end.mock.calls).toEqual([[]]);
       });
 
       it(`given content type is "${scenario.contentType}", when handler resolves with error, has error as body`, async () => {

src/main/router.ts

@@ -142,7 +142,7 @@ const handleRoute = (route: Route<any>) => async (request: LensApiRequest) => {
   if (!result) {
     const mappedResult = contentTypes.txt.resultMapper({
       statusCode: 204,
-      response: null,
+      response: undefined,
     });
 
     writeServerResponse(mappedResult);
@@ -188,5 +188,9 @@ const writeServerResponseFor =
         return;
       }
 
-      serverResponse.end(content);
+      if (content) {
+        serverResponse.end(content);
+      } else {
+        serverResponse.end();
+      }
     };