assertions.js

// Super basic assertion
// console.log(square(2) === 4);

// Now, let's try writing an assertion that gives us a little more information about what's going on.

/* Write a function, assertEqual, that takes in 3 arguments:
	- An invocation of the function you're testing
	- The expected output of the function you're testing
	- a test name for the test (string)

Output:
 - If the invocation is equivalent to the output, console.log 'Test passed'
 - If it isn't, output some error message (make sure to include the test name in the error message)

Added requirement for the function, square.
	- If a string is passed in, return an error message

*/

var square = function(num) {
	
	if (typeof num === 'string') {
		return 'Not a number! You passed in a string.';
	}

	return num * num;
}


function assertEqual(actual, expected, testName) {
	if (actual === expected) {
		return 'Test Passed';
	} else {
		return testName + ' we expected: ' + expected + ' but we got ' + actual;
	}
}

// console.log(assertEqual(square(3), 9, 'test square'));

/* Write another function, assertEqual2, where it takes in two arguments:
	- An expected behavior (should evaluate to a boolean)
	- A description of the correct behavior

It should output:
	- 'Test Passed' if the expected behavior is true
	- The description of correct behavior if the expected behavior is false
*/

function assertEqual2(expectedBehavior, descriptionOfBehavior) {
	if (expectedBehavior) {
		console.log('Test Passed');
	} else {
		console.log('Failed: ' + descriptionOfBehavior)
	}
}

assertEqual2(square(3) === 9, 'Passed in 3, expected square to return 9.');

assertEqual2(square(-3) === 9, 'Passed in -3, expected square to return 9.')

assertEqual2(square(1/3) === 1/9, 'Passed in 1/3, expected square to return 1/9.');

assertEqual2(square('hello') === 'Not a number! You passed in a string.', 'Passed in hello, expected square to return a long string');


/*
What are some other I/O (inputs/outputs) you would want to test in a square function?
 - Negative
 - Fractions
 - Decimals
 - String
 - Undefined
 - Zero
 - Really big numbers
 - Floating point numbers

*/

// Write a function called `average` that takes an array of numbers as a parameter and returns the average of those numbers.

// input: an Array of numbers, e.g. [1, 2, 3]
// output: a Number, e.g. 2

function average(numbers) {
	var total = 0;
	for (var i = 0; i < numbers.length; i++) {
		total += numbers[i];
	}
	return total / numbers.length;
}

assertEqual2(average([1, 2, 3]) === 2, 'The array of numbers, [1, 2, 3], should have returned the average value of 2');


console.log(JSON.stringify([1, 2, 3]) === JSON.stringify([1, 2, 3]));

/* Write a function called assertArraysEqual that:
	- Takes in two arguments, each one is an array
	- Returns true if the arrays are equal and false if they are not
	- Do not use JSON.stringify to do this
	- Do not use .toString to do this
	- Do not use String() to do this

*/

function assertArraysEqual(array1, array2) {
	
	// iterate through each array compare each value of the first array to the second

	var areEqual = true;

	if (array1.length !== array2.length) {
		return !areEqual;
	}

	for (var i = 0; i < array1.length; i++) {
		if (array1[i] !== array2[i]) {
			return !areEqual;

		}
	}

	return areEqual;

}
	
function areArraysEqual(array1, array2) {
	var areEqual = true;
	for (var i = 0; i < array1.length; i++) {
		if (array1[i] !== array2[i]) {
			areEqual = false;
		}
	}

	var areEqualLength = false;

	if (array1.length === array2.length) {
		areEqualLength = true;
	}

	return areEqual && areEqualLength;
}

console.log(assertArraysEqual([2, 3, 5], [1, 6, 5]));


// Using TDD, write a function that takes in an array of classmates' names and returns a new array with only names that are 6 characters or longer

var names = ['George', 'Ting', 'Gordon', 'William', 'Dennis'];

function longNames(names) {

}