[changed] oneOf doesn't include empty values

Author: jquense

src/mixed.js

@@ -315,7 +315,7 @@ SchemaType.prototype = {
       name: 'oneOf',
       test(value) {
         let valids = this.schema._whitelist
-        if (valids.length && !valids.has(value))
+        if (valids.length && !(valids.has(value) || isAbsent(value)))
           return this.createError({ params: { values: valids.values().join(', ') }})
         return true
       }

test/mixed.js

@@ -70,6 +70,20 @@ describe( 'Mixed Types ', function(){
     ])
   })
 
+  it('should ignore absent values', function(){
+    return  Promise.all([
+      mixed()
+        .oneOf(['hello'])
+        .isValid(undefined)
+        .should.eventually.equal(true),
+      string()
+        .nullable()
+        .oneOf(['hello'])
+        .isValid(null)
+        .should.eventually.equal(true)
+    ])
+  })
+
   it('should exclude values', function(){
     var inst = mixed().notOneOf(['hello', 5])