Squashed commit of the following:

commit 3d44f9682a47ff803117096f83c02745ab80598f
Author: Ben Turner <bbgrabbag@gmail.com>
Date:   Thu Oct 7 13:23:28 2021 -0600

    added custom tests

Author: bbgrabbag

README.md

@@ -41,7 +41,7 @@ module.exports = {
 // jest.config.js
 module.exports = {
     globals: {
-        testSingleChallenge: "example"
+        testSingleChallenge: "add_func"
     },
     //...
 }
@@ -53,14 +53,19 @@ module.exports = {
 // jest.config.js
 module.exports = {
     globals: {
-        testSingleChallenge: "example",
+        testSingleChallenge: "add_func",
         testSingleTestCase: 0
     },
     // ...
 }
 ```
 
-### [Changelog](./changelog.md)
+### Custom Tests
+- The default workflow in `main.test.js` may not work for some scenarios, so custom tests can be added to `custom.test.js`.
+- By default custom tests are switched off. To enable them, set the property `globals.skipCustomTests` within `jest.config.js` to `false`.
+- To run only custom tests, set the property `globals.runCustomTestsOnly` within `jest.config.js` to `true`. This will override the other settings.
 
 ### Author
 - Reach out to [Ben Turner](bbgrabbag@gmail.com) for any questions, bugs, or contribution requests.
+
+### [Changelog](./changelog.md)

custom.test.js

@@ -0,0 +1,14 @@
+/**
+ * @fileoverview - Custom tests for special scenarios can be added here.
+ */
+
+const { setCustomDescriber } = require("./utils");
+
+const describer = setCustomDescriber();
+
+/**************************************************************************************/
+describer("Custom Tests", () => {
+  it("Should run custom test", () => {
+    expect(true).toBe(true);
+  });
+});

jest.config.js

@@ -4,21 +4,29 @@
  */
 
 module.exports = {
-  // A set of global variables that need to be available in all test environments
   globals: {
-    // If defined, jest will only run tests on the function exported from this file (omit file extension) as defined in the directory '/challenges':
-
+    /*  
+    If defined, jest will only run tests on the function exported from this file (omit file extension) as defined in the directory '/challenges': 
+    */
     // testSingleChallenge: 'example',
 
-    // If defined, jest will only run test on the specified test case index. Will do nothing if the above property 'testSingleChallenge' is not also defined.
+    /* 
+    If defined, jest will only run test on the specified test case index. Will do nothing if 'testSingleChallenge' is not also defined.
+    */
+    // testSingleTestCase: 0,
+
+    /*
+    If set to 'true', only custom tests will run:
+    */
+    runCustomTestsOnly: false,
 
-    // testSingleTestCase: 0
+    /*
+    If set to 'true', custom tests will not run. Will do nothing if 'runCustomTestsOnly' is set to 'true'
+    */
+    skipCustomTests: true
   },
 
-  // Automatically clear mock calls and instances between every test
   clearMocks: true,
-
-  // Indicates which provider should be used to instrument code for coverage
   coverageProvider: "v8",
-
+  verbose: true,
 };

main.test.js

@@ -1,5 +1,6 @@
 const { testCases } = require("./test-cases");
 const functions = require("./main");
+const { setMainDescriber, setMainRunner } = require("./utils");
 
 const testCaseKeys = Object.keys(testCases);
 const functionKeys = Object.keys(functions);
@@ -12,16 +13,10 @@ try {
   for (const k of functionKeys) {
     if (!testCaseKeys.includes(k))
       throw Error(`No test case found for function '${k}()'`);
-    const describer =
-      global.testSingleChallenge === k
-        ? fdescribe
-        : describe;
+    const describer = setMainDescriber(k);
     describer(`Unit testing function '${k}()'`, () => {
       testCases[k].forEach(([inputs, expected], i) => {
-        const runner =
-        global.testSingleChallenge === k && global.testSingleTestCase === i
-            ? fit
-            : it;
+        const runner = setMainRunner(k, i);
         runner(`Should output correct value for test case '${i}'`, () => {
           expect(functions[k](...inputs)).toEqual(expected);
         });

utils.js

@@ -0,0 +1,22 @@
+module.exports = {
+  setCustomDescriber() {
+    return global.runCustomTestsOnly
+      ? fdescribe
+      : global.skipCustomTests
+      ? xdescribe
+      : describe;
+  },
+  setMainDescriber(challenge) {
+    return global.runCustomTestsOnly
+      ? xdescribe
+      : global.testSingleChallenge === challenge
+      ? fdescribe
+      : describe;
+  },
+  setMainRunner(challenge, testCaseIndex) {
+    return global.testSingleChallenge === challenge &&
+      global.testSingleTestCase === testCaseIndex
+      ? fit
+      : it;
+  }
+};