agarciany / writing-unit-tests-lab-0

Problem Set: Test Driven Development

Directions

1. Run npm install to load project dependencies.
2. See the problems below for a description of what each function is supposed to do. Each problem has 2 to 6 examples which you will write the test cases for! For example, Problem 1 has six examples, so you should write six expect statements (one testing each example). Problem 2 has four examples, so you must write four expect statements for those examples.
3. For each problem, first write the unit tests in the exercises.test.js file.
4. Then, run npm test to ensure the test case you just wrote FAILS! This is because you have not written the code for the tests yet.
5. Once you've written the tests for a problem, implement your solution to the problem in exercises.js so that it passes all test cases before moving on to the next problem.
6. Repeat Steps 3 through 5 for each problem until you have finished all problems and all test cases are correctly written and are passing.

When you are done, push your final commits and submit through Canvas.

Problems

1. Write a function that returns true if the string passed as an argument is a palindrome, or false otherwise. your function should be case-insensitive, and should ignore all non-alphanumeric characters.

isRealPalindrome('madam');               // true
isRealPalindrome('Madam');               // true (case does not matter)
isRealPalindrome("Madam, I'm Adam");     // true (only alphanumerics matter)
isRealPalindrome('356653');              // true
isRealPalindrome('356a653');             // true
isRealPalindrome('123ab321');            // false

2. Write a function that takes an array of numbers, and returns an array with the same number of elements, with each element's value being the running total from the original array.

runningTotal([2, 5, 13]);             // [2, 7, 20]
runningTotal([14, 11, 7, 15, 20]);    // [14, 25, 32, 47, 67]
runningTotal([3]);                    // [3]
runningTotal([]);                     // []

3. Given a string of words separated by spaces, write a function that swaps the first and last letters of every word. You may assume that every word contains at least one letter, and that the string will always contain at least one word. You may also assume that each string contains nothing but words and spaces, and that there are no leading, trailing, or repeated spaces.

swap('Oh what a wonderful day it is');  // "hO thaw a londerfuw yad ti si"
swap('Abcde');                          // "ebcdA"
swap('a');                              // "a"

4. Write a function that takes a string consisting of one or more space separated words, and returns an object that shows the number of words of different sizes. Words consist of any sequence of non-space characters. In the first example below, there is one sequence of length 3, one sequence of length 4, one sequence of length 5 and one sequence of length 6.

wordSizes('Four score and seven.');                       // { "3": 1, "4": 1, "5": 1, "6": 1 }
wordSizes('Hey diddle diddle, the cat and the fiddle!');  // { "3": 5, "6": 1, "7": 2 }
wordSizes("What's up doc?");                              // { "2": 1, "4": 1, "6": 1 }
wordSizes('');                                            // {}

5. Write a function that takes two arrays as arguments, and returns an array containing the union of the values from the two. There should be no duplication of values in the returned array, even if there are duplicates in the original arrays. You may assume that both arguments will always be arrays.

union([1, 3, 5], [3, 6, 9]);     // [1, 3, 5, 6, 9]
union([2, 2, 2, 2], [10, 5, 2]); // [2, 10, 5]

6. Find the first recurring character in a string. If a string does not have a recurring character, return an empty string.

firstRecurring('reuben');           // "e"
firstRecurring('anne');             // "n"
firstRecurring('restaurant');       // "r"
firstRecurring('paul');             // ""

7. Write a multiplicative average function that takes an array of integers as input, multiplies all of the integers together, divides the result by the number of entries in the array, and returns the result as a string with the value rounded to three decimal places.

showMultiplicativeAverage([3, 5]);                   // "7.500"
showMultiplicativeAverage([2, 5, 7, 11, 13, 17]);    // "28361.667"

8. Write a function that takes two array arguments, each containing a list of numbers, and returns a new array that contains the product of each pair of numbers from the arguments that have the same index. You may assume that the arguments contain the same number of elements.

multiplyList([3, 5, 7], [9, 10, 11]);  // [27, 50, 77]
multiplyList([5, 10, 15, 20], [1, 2, 3, 4]);  // [5, 20, 45, 80]

9. Write a function that takes an integer argument, and returns an array containing all integers between 1 and the argument (inclusive), in ascending order. You may assume that the argument will always be a positive integer.

sequence(5);    // [1, 2, 3, 4, 5]
sequence(3);    // [1, 2, 3]
sequence(1);    // [1]