tests: fix opn stubs

Author: shakyShane

test/specs/e2e/e2e.options.open.browsers.js

@@ -94,7 +94,8 @@ describe("E2E browser option with app args", function () {
         var stub = sinon.spy(utils, "open");
         var opnPath = require.resolve("opn");
         require(opnPath);
-        var opnStub = require("sinon").stub(require.cache[opnPath], "exports");
+        var opnStub = require("sinon").stub(require.cache[opnPath], "exports")
+            .returns({catch: function(){}});
 
         browserSync(config, function (err, bs) {
             bs.cleanup();
@@ -126,7 +127,8 @@ describe("E2E browser option with app args", function () {
         var stub = sinon.spy(utils, "open");
         var opnPath = require.resolve("opn");
         require(opnPath);
-        var opnStub = require("sinon").stub(require.cache[opnPath], "exports");
+        var opnStub = require("sinon").stub(require.cache[opnPath], "exports")
+            .returns({catch: function(){}});
 
         browserSync(config, function (err, bs) {
             bs.cleanup();

test/specs/e2e/e2e.options.open.js

@@ -50,7 +50,8 @@ describe("E2E OPEN options with external", function () {
         stub = sinon.spy(utils, "open");
         opnPath = require.resolve("opn");
         require(opnPath);
-        opnStub = require("sinon").stub(require.cache[opnPath], "exports");
+        opnStub = require("sinon").stub(require.cache[opnPath], "exports")
+            .returns({catch: function(){}});
         bs = browserSync(config, done).instance;
     });
 
@@ -81,7 +82,8 @@ describe("E2E OPEN options with UI + snippet", function () {
         stub = sinon.spy(utils, "open");
         opnPath = require.resolve("opn");
         require(opnPath);
-        opnStub = require("sinon").stub(require.cache[opnPath], "exports");
+        opnStub = require("sinon").stub(require.cache[opnPath], "exports")
+            .returns({catch: function(){}});
         bs = browserSync(config, done).instance;
     });