test(NODE-4160): add aws lambda examples

Author: durran

package.json

@@ -98,6 +98,7 @@
     "check:bench": "node test/benchmarks/driverBench",
     "check:coverage": "nyc npm run test:all",
     "check:integration-coverage": "nyc npm run check:test",
+    "check:lambda": "mocha --config test/examples/mocha_lambda.json test/examples/lambda.test.js",
     "check:lint": "npm run build:dts && npm run check:dts && npm run check:eslint && npm run check:tsd",
     "check:eslint": "eslint -v && eslint --max-warnings=0 --ext '.js,.ts' src test",
     "check:tsd": "tsd --version && tsd",

test/examples/handler.js

@@ -0,0 +1,17 @@
+// begin lambda connection
+const { MongoClient } = require('mongodb');
+
+// MongoClient now auto-connects so no need to store the connect()
+// promise anywhere and reference it.
+const client = new MongoClient(process.env.MONGODB_URI);
+
+module.exports.handler = async function () {
+  const databases = await client.db('admin').command({ listDatabases: 1 });
+  return {
+    statusCode: 200,
+    databases: databases
+  };
+};
+// end lambda connection
+
+module.exports.client = client;

test/examples/lambda.test.js

@@ -0,0 +1,26 @@
+const { expect } = require('chai');
+const { client, handler } = require('./handler');
+
+describe('AWS Lambda Examples', function () {
+  describe('#handler', function () {
+    context('when using standard authentication', function () {
+      let response;
+
+      before(async function () {
+        response = await handler();
+      });
+
+      after(async function () {
+        await client.close();
+      });
+
+      it('returns the databases', async function () {
+        expect(response.databases).to.exist;
+      });
+
+      it('returns the status code', async function () {
+        expect(response.statusCode).to.equal(200);
+      });
+    });
+  });
+});

test/examples/mocha_lambda.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://raw.githubusercontent.com/SchemaStore/schemastore/master/src/schemas/json/mocharc.json",
+  "require": [
+    "test/examples/setup.js"
+  ],
+  "extension": ["js"],
+  "ui": "test/tools/runner/metadata_ui.js",
+  "recursive": true,
+  "timeout": 6000,
+  "failZero": true,
+  "reporter": "test/tools/reporter/mongodb_reporter.js",
+  "sort": true,
+  "color": true
+}

test/examples/setup.js

@@ -0,0 +1,10 @@
+const path = require('path');
+const Module = require('module');
+const loader = Module._load;
+
+Module._load = function(request, loc) {
+  if (request === 'mongodb') {
+    arguments[0] = path.join(__dirname, '..', '..', 'lib');
+  }
+  return loader.apply(this, arguments);
+};