Add tests for sanitize.js

Installs rewire from npm and use it to test functions
in sanitize.js

Part of https://github.com/bigchaindb/js-bigchaindb-driver/issues/220

package.json

@@ -80,6 +80,7 @@
     "js-utility-belt": "^1.5.0",
     "json-stable-stringify": "^1.0.1",
     "query-string": "^6.0.0",
+    "rewire": "^4.0.1",
     "sprintf-js": "^1.1.1",
     "tweetnacl": "^1.0.0",
     "uglifyjs-webpack-plugin": "^1.2.7",

test/sanitize/test_sanitize.js

@@ -0,0 +1,60 @@
+import test from 'ava'
+import rewire from 'rewire'
+
+const sanitize = rewire('../../src/sanitize.js')
+const applyFilterOnObject = sanitize.__get__('applyFilterOnObject')
+const filterFromObject = sanitize.__get__('filterFromObject')
+
+
+test('Ensure that null filter returns same object', t => {
+    const expected = { 'testObj': 'test' }
+    const actual = applyFilterOnObject({ 'testObj': 'test' }, null)
+
+    t.deepEqual(actual, expected)
+})
+
+
+test('Ensure function filter with isInclusion true works properly', t => {
+    const testObj = [true, false, undefined, '', 0, null]
+    const expected = { 0: true }
+    const actual = filterFromObject(testObj, (val) => !!val, { isInclusion: true })
+
+    t.deepEqual(actual, expected)
+})
+
+
+test('Ensure function filter with isInclusion false works properly', t => {
+    const testObj = [false, true, 1, 10, 'this will be removed as it is truthy']
+    const expected = { 0: false }
+    const actual = filterFromObject(testObj, (val) => !!val, { isInclusion: false })
+
+    t.deepEqual(actual, expected)
+})
+
+
+test('Ensure array filter with isInclusion true works properly', t => {
+    const testObj = [true, false, undefined, '', 0, null]
+    const expected = { 0: true }
+    const actual = filterFromObject(testObj, [true], { isInclusion: true })
+
+    t.deepEqual(actual, expected)
+})
+
+
+test('Ensure array filter with isInclusion false works properly', t => {
+    const testObj = [false, true, 1, 10]
+    const expected = { 0: false }
+    const actual = filterFromObject(testObj, [true, 1, 10], { isInclusion: false })
+
+    t.deepEqual(actual, expected)
+})
+
+
+test('Ensure throws error when given invalid filter', t => {
+    const error = t.throws(() => {
+        filterFromObject({}, 'lol')
+    }, Error)
+
+    t.is(error.message, 'The given filter is not an array or function. Filter aborted')
+})
+