first

Author: rclark

.eslintrc

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+{
+  "rules": {
+    "indent": [2, 2],
+    "quotes": [2, "single"],
+    "quote-props": [2, "as-needed"],
+    "no-console": [1],
+    "semi": [2, "always"],
+    "space-before-function-paren": [2, "never"],
+    "object-curly-spacing": [2, "always"],
+    "array-bracket-spacing": [2, "never"],
+    "comma-spacing": [2, { "before": false, "after": true }],
+    "key-spacing": [2, { "beforeColon": false, "afterColon": true }]
+  },
+  "env": {
+      "node": true,
+      "es6": true
+  },
+  "globals": {
+      "process": true,
+      "module": true,
+      "require": true
+  },
+  "extends": "eslint:recommended"
+}

.gitignore

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+node_modules/
+.nyc_output/
+coverage/

index.js

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+var events = require('events');
+var sinon = require('sinon');
+var _AWS = require('aws-sdk');
+var traverse = require('traverse');
+
+module.exports = _AWS;
+module.exports.stub = stubMethod;
+
+/**
+ * Replaces a single AWS service method with a stub.
+ *
+ * @param {string} service - the name of the AWS service. Can include `.` for
+ * nested services, e.g. `'DynamoDB.DocumentClient'`.
+ * @param {string} method - the name of the service method to stub.
+ * @param {function} [replacement] - if specified, this function will be called
+ * when the service method stub is invoked. `this` in the context of the function
+ * will provide a reference to stubbed AWS.Request and AWS.Response objects to
+ * simulate more advanced aws-sdk-js usage patterns.
+ * @returns {object} stub - [a sinon stub](http://sinonjs.org/docs/#stubs).
+ */
+function stubMethod(service, method, replacement) {
+  if (!isStubbed(service)) stubService(service);
+  if (!replacement) return sinon.stub(getService(service).prototype, method);
+
+  return sinon.stub(getService(service).prototype, method, function(params, callback) {
+    var _this = { request: stubRequest(), response: stubResponse() };
+    replacement.call(_this, params, callback);
+    return _this.request;
+  });
+}
+
+function isStubbed(service) {
+  return getService(service).isSinonProxy;
+}
+
+function getService(name) {
+  return traverse(_AWS).get(name.split('.'));
+}
+
+function setService(name, fn) {
+  traverse(_AWS).set(name.split('.'), fn);
+}
+
+function stubService(service) {
+  var Original = getService(service);
+  var client = new Original();
+
+  function FakeService(config) { Object.assign(this, new Original(config)); }
+  FakeService.prototype = Object.assign({}, client.__proto__);
+
+  var spy = sinon.spy(FakeService);
+  spy.restore = function() { setService(service, Original); };
+
+  setService(service, spy);
+}
+
+function stubRequest() {
+  var req = new events.EventEmitter();
+  var stubbed = sinon.createStubInstance(_AWS.Request);
+  for (var method in req.__proto__) delete stubbed[method];
+  return Object.assign(req, stubbed);
+}
+
+function stubResponse() {
+  var req = new events.EventEmitter();
+  var stubbed = sinon.createStubInstance(_AWS.Response);
+  for (var method in req.__proto__) delete stubbed[method];
+  return Object.assign(req, stubbed);
+}

package.json

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+{
+  "name": "@mapbox/mock-aws-sdk-js",
+  "version": "0.0.1",
+  "description": "Create stubbed aws-sdk-js clients for testing purposes",
+  "main": "index.js",
+  "engines": {
+    "node": ">4.0.0"
+  },
+  "scripts": {
+    "pretest": "eslint index.js test",
+    "test": "nyc tape test/*.test.js",
+    "coverage": "nyc --reporter html tape test/*.test.js && opener coverage/index.html"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/mapbox/mock-aws-sdk-js.git"
+  },
+  "keywords": [
+    "aws",
+    "mock",
+    "sinon",
+    "testing"
+  ],
+  "author": "Mapbox",
+  "license": "ISC",
+  "bugs": {
+    "url": "https://github.com/mapbox/mock-aws-sdk-js/issues"
+  },
+  "homepage": "https://github.com/mapbox/mock-aws-sdk-js#readme",
+  "peerDependencies": {
+    "aws-sdk": "^2.5.0"
+  },
+  "dependencies": {
+    "sinon": "^1.17.5",
+    "traverse": "^0.6.6"
+  },
+  "devDependencies": {
+    "eslint": "^3.5.0",
+    "nyc": "^8.1.0",
+    "opener": "^1.4.2",
+    "tape": "^4.6.0"
+  }
+}

readme.md

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+# @mapbox/mock-aws-sdk-js
+
+A library that provides sinon-style stubs for aws-sdk-js service methods for use in testing.
+
+### Goals
+
+- allow tests to make assertions about both service client configuration (e.g. region) and method arguments
+- enable tests for application logic with varied usage of `AWS.Request` object methods
+
+### Basic usage
+
+Your application, `app.js`:
+
+```js
+var AWS = require('aws-sdk');
+
+module.exports = function(callback) {
+  // It is important that aws-sdk clients be defined in a function, and not
+  // as module-level variables.
+  var s3 = new AWS.S3({ region: 'eu-west-1' });
+  s3.getObject({ Bucket: 'bucket', Key: 'key' }, function(err, data) {
+    if (err) return callback(err);
+    callback(null, data.Body.toString());
+  });
+}
+```
+
+Your test script:
+
+```js
+var test = require('tape');
+var app = require('./app');
+var AWS = require('@mapbox/mock-aws-sdk-js');
+
+test('gets S3 object', function(assert) {
+  var data = { Body: new Buffer('hello world') };
+  var expected = { Bucket: 'bucket', Key: 'key' };
+
+  var getObject = AWS.stub('S3', 'getObject', function(params, callback) {
+    callback(null, data);
+  });
+
+  app(function(err, data) {
+    assert.ifError(err, 'success');
+    assert.equal(data, 'hello world');
+
+    assert.equal(AWS.S3.callCount, 1, 'one s3 client created');
+    assert.ok(AWS.S3.calledWithExactly({ region }), 's3 client created for the correct region');
+
+    assert.equal(getObject.callCount, 1, 'called s3.getObject once');
+    assert.ok(getObject.calledWith(expected), 'called s3.getObject with expected params');
+
+    AWS.S3.restore();
+    assert.end();
+  });
+});
+```
+
+Read all about [how to use sinon stubs here](http://sinonjs.org/docs/#stubs).
+
+### More examples
+
+`test/test-app.js` represents a module that makes the same basic S3.getObject request in several different ways. `test/index.test.js` then contains a number of examples for how you might choose to write tests for the module.