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changed repo-name to rewire
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‎README.md‎

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@@ -1,4 +1,61 @@
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trick
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=====
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Dependency injection for node.js applications
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rewire
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=====
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**Dependency injection for node.js applications**.
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rewire allows you to modify the behaviour of modules for better unit testing. You may
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- provide mocks for other modules
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- leak private variables
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- override variables within the module
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- inject scripts
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rewire does **not** load the file and eval it to emulate node's require mechanism. In fact it uses node's require to load the module. Thus your module behaves exactly the same in your test environment as under regular circumstances (except your modifications).
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Installation
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------------
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```npm install rewire```
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Examples
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--------
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```javascript
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var rewire = require("rewire"),
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rewiredModule;
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// Default
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////////////////////////////////
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// rewire acts exactly like require when omitting all other params
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rewiredModule = rewire("./myModuleA.js");
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// Mocks
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////////////////////////////////
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var mockedModuleB = {},
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mocks = {
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"path/to/moduleB.js": mockedModuleB
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};
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// the rewired module will now use your mock instead of moduleB.js.
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rewiredModule = rewire("./myModuleA.js", mocks);
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// Injections
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////////////////////////////////
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var injections = {
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console: {
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log: function () { /* be quiet */ }
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},
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process: { argv: ["someArgs"] },
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__filename: "some/other/dir"
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};
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// overrides all given variables within the module
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rewiredModule = rewire("./myModuleA.js", null, injections);
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// you can also pass a script to inject
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rewiredModule = rewire("./myModuleA.js", null, "console.log('hellooo');");
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// Leaks
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////////////////////////////////
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```

‎lib/index.js‎

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@@ -1,6 +1,6 @@
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"use strict"; // run code in ES5 strict mode
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var trick = require("./trick.js");
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var rewire = require("./rewire.js");
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module.exports = function (request, mocks, injections, leaks, cache) {
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delete require.cache[__filename]; // deleting self from module cache so the parent module is always up to date
@@ -9,5 +9,5 @@ module.exports = function (request, mocks, injections, leaks, cache) {
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cache = true;
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}
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return trick(module.parent, request, mocks, injections, leaks, cache);
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return rewire(module.parent, request, mocks, injections, leaks, cache);
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};

‎lib/trick.js‎ renamed to ‎lib/rewire.js‎

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@@ -7,13 +7,13 @@ var Module = require("module"),
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getInjectionSrc = require("./getInjectionSrc.js");
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function restoreOriginalWrappers() {
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Module.wrapper[0] = nodeWrapper0;
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Module.wrapper[1] = nodeWrapper1;
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}
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function trick(parentModule, filename, mocks, injections, leaks, cache) {
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function rewire(parentModule, filename, mocks, injections, leaks, cache) {
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var testModule,
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nodeRequire;
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nodeRequire,
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wrapperExtensions = "";
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function requireTrick(path) {
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restoreOriginalWrappers(); // we need to restore the wrappers now so we don't influence other modules
@@ -37,15 +37,16 @@ function trick(parentModule, filename, mocks, injections, leaks, cache) {
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// Prepare module for injection
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if (typeof injections === "object") {
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Module.wrapper[0] = nodeWrapper0 + getInjectionSrc(injections);
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wrapperExtensions += getInjectionSrc(injections);
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} else if (typeof injections === "string") {
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Module.wrapper[0] = nodeWrapper0 + injections;
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wrapperExtensions += injections;
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}
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// Prepare module for leaking private vars
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if (Array.isArray(leaks)) {
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Module.wrapper[1] = getLeakingSrc(leaks) + nodeWrapper1;
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wrapperExtensions += getLeakingSrc(leaks);
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}
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Module.wrapper[1] = wrapperExtensions + nodeWrapper1;
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// Mocking module.require-function
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testModule.require = requireTrick;
@@ -61,4 +62,4 @@ function trick(parentModule, filename, mocks, injections, leaks, cache) {
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return testModule.exports;
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}
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module.exports = trick;
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module.exports = rewire;

‎package.json‎

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{
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"name" : "trick",
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"name" : "rewire",
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"version" : "0.1.0",
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"description" : "Dependency injection for node.js applications",
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"keywords" : [
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"main" : "lib/index.js",
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"bugs" : {
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"email" : "mail@johannesewald.de",
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"url" : "https://github.com/jhnns/trick/issues"
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"url" : "https://github.com/jhnns/rewire/issues"
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},
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"licenses" : {
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"type" : "MIT",
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"url" : "http: //www.opensource.org/licenses/mit-license.php"
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},
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"repositories" : {
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"type" : "git",
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"url" : "https://github.com/jhnns/trick"
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"url" : "https://github.com/jhnns/rewire"
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},
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"engines" : {
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"node" : "0.6.x"

‎test/debug.test.js‎

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"use strict"; // run code in ES5 strict mode
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var rewire = require("../lib/index.js");
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// add breakpoints in testModules/debuggerModule.js and debug this file with your IDE to
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// check if debugging works with rewire.
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var debuggerModule = rewire("./testModules/debuggerModule.js", null, {
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someVar: "Look if you can see me in your IDE when holding at the breakpoints"
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});
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debuggerModule();

‎test/rewire.test.js‎

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"use strict"; // run code in ES5 strict mode
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var path = require("path"),
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expect = require("expect.js"),
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rewire = require("../lib/index.js");
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var testModules = [
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path.resolve(__dirname, "./testModules/index.js"),
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path.resolve(__dirname, "./testModules/A/moduleA.js"),
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path.resolve(__dirname, "./testModules/B/moduleB.js"),
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path.resolve(__dirname, "./testModules/C/moduleC.js")
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];
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function cleanRequireCache() {
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var i;
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for (i = 0; i < testModules.length; i++) {
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delete require.cache[testModules[i]];
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}
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}
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describe("#rewire", function () {
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beforeEach(cleanRequireCache); // ensuring a clean test environment
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it("should work like require() when omitting all other params", function () {
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expect(rewire("./testModules/A/moduleA.js")).to.be(require("./testModules/A/moduleA.js"));
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});
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it("should require all mocks", function () {
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var rewired,
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fsMock = {},
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mocks = {},
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moduleBMock = {},
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moduleCMock = {},
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toSrcMock = {},
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indexMock = {};
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mocks["fs"] = fsMock;
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mocks[path.resolve(__dirname, "./testModules/B/moduleB.js")] = moduleBMock;
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mocks["../C/moduleC.js"] = moduleCMock;
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mocks["toSrc"] = toSrcMock;
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mocks["../"] = indexMock;
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rewired = rewire("./testModules/A/moduleA.js", mocks);
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expect(rewired.fs).to.be(fsMock);
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expect(rewired.b).to.be(moduleBMock);
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expect(rewired.c).to.be(moduleCMock);
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expect(rewired.toSrc).to.be(toSrcMock);
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expect(rewired.index).to.be(indexMock);
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});
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it("should inject object modifications", function () {
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var rewired,
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injections = {
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process: {
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argv: ["arg1", "arg2", "arg3"]
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},
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console: 123
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};
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rewired = rewire("./testModules/A/moduleA.js", null, injections);
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rewired.exportAll();
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expect(rewired.process).not.to.be(process);
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expect(process.argv).not.to.eql(injections.process.argv);
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expect(rewired.process).to.eql(injections.process);
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expect(rewired.console).to.be(123);
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});
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it("should inject custom scripts", function () {
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var rewired,
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script = "var console = 456;";
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rewired = rewire("./testModules/A/moduleA.js", null, script);
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rewired.exportAll();
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expect(rewired.console).to.be(456);
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});
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it("should leak private variables", function () {
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var rewired,
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leaks = ["myPrivateVar"];
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rewired = rewire("./testModules/A/moduleA.js", null, null, leaks);
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expect(rewired.__.myPrivateVar).to.be("Hello I'm very private");
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});
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it("should leak private functions", function () {
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var rewired,
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leaks = ["myPrivateFunction"];
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rewired = rewire("./testModules/A/moduleA.js", null, null, leaks);
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expect(rewired.__.myPrivateFunction()).to.be("Hello I'm very private");
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});
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it("should leak nothing on demand", function () {
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var rewired;
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rewired = rewire("./testModules/A/moduleA.js");
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expect(rewired.__).to.be(undefined);
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});
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it("should cache the rewired module", function () {
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var rewired;
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rewired = rewire("./testModules/B/moduleB.js");
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rewired.requireIndex();
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expect(rewired.index.b).to.be(rewired);
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cleanRequireCache();
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rewired = rewire("./testModules/B/moduleB.js", null, null, null, true);
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rewired.requireIndex();
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expect(rewired.index.b).to.be(rewired);
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});
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it("should not cache the rewired module on demand", function () {
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var rewired;
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rewired = rewire("./testModules/B/moduleB.js", null, null, null, false);
109+
rewired.requireIndex();
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expect(rewired.index.b).not.to.be(rewired);
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});
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});

‎test/testModules/A/moduleA.js‎

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@@ -11,11 +11,22 @@ var path = require("path"),
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var myPrivateVar = "Hello I'm very private";
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14-
// expose all required modules to test for mocks
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exports.fs = fs;
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exports.b = b;
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exports.c = c;
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exports.toSrc = toSrc;
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exports.index = index;
20-
exports.process = process;
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exports.console = console;
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function myPrivateFunction() {
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return "Hello I'm very private";
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}
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function exportAll() {
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// expose all required modules to test for mocks
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exports.fs = fs;
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exports.b = b;
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exports.c = c;
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exports.toSrc = toSrc;
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exports.index = index;
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exports.process = process;
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exports.console = console;
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}
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exportAll();
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exports.exportAll = exportAll;
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‎test/testModules/debuggerModule.js‎

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"use strict"; // run code in ES5 strict mode
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// Add a breakpoint on line 6 and on line 11 and debug "debug.test.js" to test if the IDE stops at these points.
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// Watch also the variable someVar that is injected by rewire. It will be undefined at this point because
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// all injections are executed at the end of the module.
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// It's already visible because of hoisting: http://net.tutsplus.com/tutorials/javascript-ajax/quick-tip-javascript-hoisting-explained/)
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var someNumber = 0;
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module.exports = function () {
10+
// In this line someVar will be defined.
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someNumber++;
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someVar;
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};

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