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1 files changed, 114 insertions, 0 deletions

diff --git a/src/node_modules/chance/test/test.normal.js b/src/node_modules/chance/test/test.normal.js
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+++ b/src/node_modules/chance/test/test.normal.js
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+import test from 'ava'
+import Chance from '../chance.js'
+import _ from 'lodash'
+
+// Helper methods
+const mean = (arr) => arr.reduce((a, b) => a + b)/arr.length
+const stddev = (arr) => {
+    var testMean = mean(arr)
+    var deviation = arr.map((item) => (item - testMean) * (item - testMean))
+    return Math.sqrt(deviation.reduce((a, b) => a + b )/arr.length)
+}
+
+const pool = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
+
+const chance = new Chance()
+
+test('normal() works as expected with no parameters and returns a number', t => {
+    _.times(1000, () => {
+        let norm = chance.normal()
+        t.is(typeof norm, 'number')
+    })
+})
+
+test('normal() returns values fairly close to the expected standard deviation and mean', t => {
+    let testStddev = 1
+    let testMean = 0
+    let group = chance.n(chance.normal, 10000)
+
+    t.true(Math.abs(mean(group) - testMean) < testStddev)
+    t.true(Math.abs(stddev(group) - testStddev) < testStddev * 0.05)
+})
+
+test('normal() works as expected with a pool of custom values provided', t => {
+    let testStddev = 0.0000000001
+    let testMean = 2
+
+    _.times(1000, () => {
+        let norm = chance.normal({ mean: testMean, dev: testStddev, pool: pool })
+        t.true(pool.indexOf(norm) !== -1)
+    })
+})
+
+test('normal() recalculates and returns a value even if the normal() results in indexes outside the bounds of the pool', t => {
+    let testStddev = 1.5
+    let testMean = 3
+
+    _.times(1000, () => {
+        let norm = chance.normal({ mean: testMean, dev: testStddev, pool: pool })
+        t.true(pool.indexOf(norm) !== -1)
+    })
+})
+
+test('normal() can be used with other chance functions', t => {
+    let testStddev = 1
+    let testMean = 3
+    let group = chance.n(chance.normal, 1000, { mean: testMean, dev: testStddev, pool: pool })
+
+    t.true(group.length === 1000)
+    t.true(pool.indexOf(group[0]) !== -1)
+    t.true(pool.indexOf(group[999]) !== -1)
+})
+
+test('normal() should produce a correctly distributed group of pool items', t => {
+    let testStddev = 2
+    let testMean = 6
+    let group = chance.n(chance.normal, 10000, { mean: testMean, dev: testStddev, pool: pool })
+    let counts = _.countBy(group)
+
+    t.true(counts.Sunday > counts.Saturday)
+    t.true(counts.Saturday > counts.Friday)
+    t.true(counts.Friday > counts.Thursday)
+    t.true(counts.Thursday > counts.Wednesday)
+    t.true(counts.Wednesday > counts.Tuesday)
+    t.true(counts.Tuesday > counts.Monday)
+})
+
+test('normal() should throw an error quickly if the user has provided bad pool', t => {
+    let testStddev = 5
+    let testMean = 200
+    const fn = () => chance.normal({ mean: testMean, dev: testStddev, pool: pool })
+    t.throws(fn, 'Chance: Your pool is too small for the given mean and standard deviation. Please adjust.')
+})
+
+test('normal() should throw an error if called with non-number mean', t => {
+    let testStddev = 5
+    let testMean = []
+    const fn = () => chance.normal({ mean: testMean, dev: testStddev, pool: pool })
+    t.throws(fn, 'Chance: Mean (mean) must be a number')
+})
+
+test('normal() should throw an error if called with non-number stddev', t => {
+    let testStddev = []
+    let testMean = 5
+    const fn = () => chance.normal({ mean: testMean, dev: testStddev, pool: pool })
+    t.throws(fn, 'Chance: Standard deviation (dev) must be a number')
+})
+
+test('normal() should throw an error if the pool provided is not an array', t => {
+    const fn = () => chance.normal({ pool: 'not an array' })
+    t.throws(fn, 'Chance: The pool option must be a valid array.')
+})
+
+test('normal() should work with objects', t => {
+    let testStddev = 1
+    let testMean = 1
+    let group = chance.n(chance.normal, 50, { mean: testMean, dev: testStddev, pool: [
+        { a: 1, b: 10},
+        { a: 2, b: 20},
+        { a: 3, b: 30}
+    ]})
+
+    t.true(group.length === 50)
+    t.truthy(group[0]['a'])
+})