test for SW caching a successfully fetched config.json (ref. #31)

__tests__/service-worker.test.js

@@ -293,6 +293,51 @@ describe("service-worker", () => {
     expect(self.LibResilientConfig.loggedComponents).toStrictEqual(['service-worker', 'cache'])
   })
   
+  test("basic set-up: a valid config.json file gets cached", async () => {
+    self.LibResilientConfig = null
+    
+    var configData = {loggedComponents: ['service-worker', 'cache'], plugins: [{name: "cache"}], defaultPluginTimeout: 5000}
+    global.fetch.mockImplementation((url, init) => {
+        return Promise.resolve(
+                new Response(
+                    new Blob(
+                        [JSON.stringify(configData)],
+                        {type: "application/json"}
+                    ),
+                    {
+                        status: 200,
+                        statusText: "OK",
+                        headers: {
+                        'ETag': 'TestingETagHeader'
+                        },
+                        url: url
+                    })
+                );
+    });
+    
+    try {
+      require("../service-worker.js");
+    } catch(e) {}
+    await self.trigger('install')
+    // this is silly but works, and is necessary because
+    // event.waitUntil() in the install event handler is not handled correctly in NodeJS
+    await new Promise(resolve => resolve(true))
+    await self.trigger('activate')
+    expect(typeof self.LibResilientConfig).toEqual('object')
+    expect(self.LibResilientConfig.defaultPluginTimeout).toBe(5000)
+    expect(self.LibResilientConfig.plugins).toStrictEqual([{name: "cache"}])
+    expect(self.LibResilientConfig.loggedComponents).toStrictEqual(['service-worker', 'cache'])
+    // this is silly but works, and is necessary because... who knows, honestly?
+    await new Promise(resolve => resolve(true))
+    expect (await caches.open('v1').then((cache)=>{
+                return cache.match(self.location.origin + '/config.json')
+            }).then((response)=>{
+                return response.json()
+            }).then((json)=>{
+                return json
+            })).toStrictEqual({loggedComponents: ['service-worker', 'cache'], plugins: [{name: "cache"}], defaultPluginTimeout: 5000})
+  })
+  
   test("fetching content should work", async () => {
     self.LibResilientConfig = {
         plugins: [{