Implement helpers module with formatLongString()

lib/helpers/helpers.spec.coffee

@@ -0,0 +1,35 @@
+expect = require('chai').expect
+_ = require('lodash')
+helpers = require('./helpers')
+
+STRING =
+	numbers: '1234567812345678'
+
+describe 'Helpers:', ->
+
+	describe '#formatLongString()', ->
+
+		it 'should format a string', ->
+			result = helpers.formatLongString(STRING.numbers, 4)
+			expect(result).to.equal('1234\n5678\n1234\n5678')
+
+		it 'should return the same string if n is null/undefined', ->
+			for value in [ undefined, null ]
+				result = helpers.formatLongString(STRING.numbers, value)
+				expect(result).to.equal(STRING.numbers)
+
+		it 'should throw an error if input is not a string', ->
+			for value in [
+				undefined
+				null
+				[]
+				{}
+				123
+			]
+				fn = _.partial(helpers.formatLongString, value, 4)
+				expect(fn).to.throw
+
+		it 'should return the same string if n > string.length', ->
+			stringLength = STRING.numbers.length
+			result = helpers.formatLongString(STRING.numbers, stringLength + 1)
+			expect(result).to.equal(STRING.numbers)