add unit test coverage to init lifecycle hook feature

Author: dancfox

test/unit/utils/UserFunction.test.ts

@@ -0,0 +1,45 @@
+/** Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. */
+
+"use strict";
+
+require("should");
+import { load } from "../../../src/utils/UserFunction";
+
+describe("Invoking the load function", async() => {
+    it("should not fail when init hook function is present", async() => {
+        const handler = "InitPresent.handler"
+        const appRoot = "test/unit/utils/function";
+
+        const handlerFunc = (await load(
+            appRoot,
+            handler
+        )) as Function;
+
+        handlerFunc.should.be.Function;
+        handlerFunc.should.not.be.null;
+    });
+    it("should not fail when init hook function is absent", async() => {
+        const handler = "InitAbsent.handler"
+        const appRoot = "test/unit/utils/function";
+
+        const handlerFunc = (await load(
+            appRoot,
+            handler
+        )) as Function;
+
+        handlerFunc.should.be.Function;
+        handlerFunc.should.not.be.null;
+    });
+    it("should catch TypeError exception", async() => {
+        const handler = "InitThrowsTypeError.handler"
+        const appRoot = "test/unit/utils/function";
+
+        const handlerFunc = (await load(
+            appRoot,
+            handler
+        )) as Function;
+
+        handlerFunc.should.be.Function;
+        handlerFunc.should.not.be.null;
+    });
+});

test/unit/utils/function/InitAbsent.js

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+exports.handler = async (event, context) => {
+    return 'Function complete.';
+}

test/unit/utils/function/InitPresent.js

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+// console.log("******** enter the init block   ********");
+
+let resolved = "No";
+
+function sleep(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms)).then(() => {resolved = "Yes!"});
+}
+
+exports.initializeFunction = async () => {
+  // console.log("******** enter initializeFunction hook ********");
+  // console.log("******** Is promised resolved? " + resolved + " ********");
+  // console.log("******** sleep for 20 ms... ********")
+  let p = await sleep(20);
+  // console.log("******** wake up                ********");
+  // console.log("******** Is promised resolved? " + resolved + " ********");
+}
+
+exports.handler = async (event, context) => {
+    // console.log("******** enter the handler        ********");
+    // console.log("******** Is promised resolved? " + resolved + " ********");
+
+    return 'Function complete.';
+}

test/unit/utils/function/InitThrowsTypeError.js

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+exports.initializeFunction = async () => {
+    throw new TypeError;
+}
+
+exports.handler = async (event, context) => {
+    return 'Function complete.';
+}