test(open-option): fix test

Author: hiroppy

lib/utils/runOpen.js

@@ -4,13 +4,11 @@ const open = require('opn');
 
 function runOpen(uri, options, log) {
   // https://github.com/webpack/webpack-dev-server/issues/1990
-  const openOptions = { wait: false };
+  let openOptions = { wait: false };
   let openMessage = 'Unable to open browser';
 
   if (typeof options.open === 'string') {
-    Object.assign(openOptions, {
-      app: options.open,
-    });
+    openOptions = Object.assign({}, openOptions, { app: options.open });
     openMessage += `: ${options.open}`;
   }
 

test/server/open-option.test.js

@@ -21,9 +21,18 @@ describe('open option', () => {
     });
 
     compiler.hooks.done.tap('webpack-dev-server', () => {
-      expect(opn.mock.calls[0]).toEqual(['http://localhost:8080/', {}]);
-      expect(opn.mock.invocationCallOrder[0]).toEqual(1);
-      server.close(done);
+      server.close(() => {
+        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+          Array [
+            "http://localhost:8080/",
+            Object {
+              "wait": false,
+            },
+          ]
+        `);
+        expect(opn.mock.invocationCallOrder[0]).toEqual(1);
+        done();
+      });
     });
 
     compiler.run(() => {});