cleaner tests

__tests__/plugins/fetch.test.js

@@ -1,17 +1,18 @@
-var self = self || global;
-
-self.LibResilientPlugins = new Array()
-
-self.LibResilientConfig = {
-    plugins: {
-        'fetch':{}
-    }
-}
-
-const fetchPlugin = require("../../plugins/fetch.js");
+const makeServiceWorkerEnv = require('service-worker-mock');
 
 describe("fetch() plugin", () => {
+  beforeEach(() => {
+    Object.assign(global, makeServiceWorkerEnv());
+    jest.resetModules();
+    self.LibResilientPlugins = new Array()
+    self.LibResilientConfig = {
+        plugins: {
+            'fetch':{}
+        }
+    }
+  })
   test("it should register in LibResilientPlugins", () => {
+    require("../../plugins/fetch.js");
     expect(self.LibResilientPlugins[0].name).toEqual('fetch');
   });
 });

plugins/fetch.js

@@ -2,8 +2,6 @@
 |* === Regular HTTP(S) fetch() plugin                                    === *|
 \* ========================================================================= */
 
-var self = self || global;
-
 /**
  * this plugin does not implement any push method
  */