Failure

Author: carvallegro

katas/potter/index.js

@@ -11,22 +11,40 @@ const DISCOUNTS = [0,
 const BOOKS = [0,1,2,3,4]
 
 function potter(books = []){
+    const invalidBooks = books.filter( num => num < 0 && num > 4 )
+    if (invalidBooks.length > 0){
+        throw new Error("Invalid book number!")
+    } 
+
     let totalPrice = 0
-    let freqList = freq(books)
 
-    freqList.filter((f) => {
-        return f != 0
-    })
-    totalPrice += BASE_PRICE * freqList.length * DISCOUNTS[freqList.length]
-    return totalPrice
+    for (let freqList = freq(books); freqList.length > 0; freqList = removeSet(freqList)){
+        freqList = removeZeros(freqList)
+
+        totalPrice += calculateSetPrice(freqList.length)
+    }
+    return totalPrice 
 }
+
 function freq(books=[]){
     const countingBooks = [0, 0, 0, 0, 0]
     books.forEach((book) => {
         countingBooks[book] += 1
     })
     return countingBooks
 }
+
+function removeZeros (array) {
+    return array.filter(number => number != 0)
+}
 
+function calculateSetPrice (setSize = 0) {
+    return BASE_PRICE * setSize * DISCOUNTS[setSize]
+}
+
+function removeSet(array){
+    return array.map(x => x-1)
+
+}
 
-module.exports={potter, freq};
+module.exports={potter, freq, removeZeros, calculateSetPrice, removeSet };

katas/potter/index.test.js

@@ -1,31 +1,64 @@
 const _ = require('lodash');
-const {it, describe} = require('mocha');
-const {assert,expect} = require('chai')
+const { it, describe } = require('mocha');
+const { assert, expect } = require('chai')
 
-const {potter,freq} = require('./index')
+const { potter, freq, removeZeros, calculateSetPrice, removeSet } = require('./index')
 
 describe('the Potter discounts', () => {
   it('should return 0 if nothing given', () => {
     expect(potter()).to.equal(0);
   });
 
-  it('should return the appropriate discount for different books', () =>{
+  it('should return the appropriate discount for different books', () => {
     expect(potter([0])).to.equal(8);
-    expect(potter([0,1])).to.equal(15.2);
-    expect(potter([0,1,2])).to.equal(21.6);
-    expect(potter([0,1,2,3])).to.equal(25.6);
-    expect(potter([0,1,2,3,4])).to.equal(30)
-  })
+    expect(potter([0, 1])).to.equal(15.2);
+    expect(potter([0, 1, 2])).to.equal(21.6);
+    expect(potter([0, 1, 2, 3])).to.equal(25.6);
+    expect(potter([0, 1, 2, 3, 4])).to.equal(30)
+  });
 
-  it('should not apply discount for two same books',
-  ()=>{
-      expect(potter([0,0])).to.equal(16);
-  })
+  it('should return the correct prices', () => {
+    expect(potter([1, 2, 3, 1, 2, 3, 4, 3])).to.equal(55.2);
+    expect(potter([2, 2, 2, 2, 2, 4, 3, 1, 1])).to.equal(64.8);
+    expect(potter([0, 1, 2, 4, 2, 3, 2, 1, 0, 0])).to.equal(66.8);
+    expect(potter([1, 1, 1, 1, 1, 1, 2])).to.equal(55.2);
+    expect(potter([2, 3, 4, 0, 0, 1])).to.equal(38);
+  });
+
+  // it('should throw an error if book number is invalid', () => {
+  //   expect(() => potter([1, 1, 1, 1, 1, 1, 6])).to.throw();
+  // })
+
+  it('should not apply discount for two same books', () => {
+      expect(potter([0, 0])).to.equal(16);
+    })
 })
 describe('the frequence function', () => {
-    it('should retunr the frequency function', () => {
-        expect(freq([1,1,2,2])).to.deep.equal([0,2,2,0,0])
-});
+  it('should retunr the frequency function', () => {
+    expect(freq([1, 1, 2, 2])).to.deep.equal([0, 2, 2, 0, 0])
+  });
 });
 
+describe('removing zeros from frequency array', () => {
+  it('should remove zeros from the array', () => {
+    expect(removeZeros([0, 0, 1, 2, 1])).to.deep.equal([1, 2, 1])
+  })
+})
+
+describe('return the price of the set', () => {
+  it('should calculate the price including correct discount', () => {
+    expect(calculateSetPrice(1)).to.equal(8);
+    expect(calculateSetPrice(2)).to.equal(15.2);
+    expect(calculateSetPrice(3)).to.equal(21.6);
+    expect(calculateSetPrice(4)).to.equal(25.6);
+    expect(calculateSetPrice(5)).to.equal(30)
+  })
+})
+
+describe('removing the calculated set from the frequency array', () => {
+  it('should remove 1 from each element of the array', () => {
+    expect(removeSet([1, 2, 1])).to.deep.equal([0, 1, 0])
+  })
+})
+