Use new feature of a/an assertion to check type of tested object when…

… using include assertion

lib/chai/core/assertions.js

@@ -211,13 +211,7 @@ module.exports = function (chai, _) {
     var obj = flag(this, 'object');
     var expected = false;
 
-    if (_.type(obj) !== 'array' && _.type(obj) !== 'string' && _.type(obj) !== 'object') {
-      this.assert(
-          false
-        , 'argument of expect() must be an array, an object, or a string, ' + _.type(obj) + ' given'
-        , 'argument of expect() must be an array, an object, or a string, ' + _.type(obj) + ' given');
-      return;
-    }
+    new Assertion(obj).to.be.a(['array', 'object', 'string']);
 
     if (_.type(obj) === 'array' && _.type(val) === 'object') {
       for (var i in obj) {

test/assert.js

@@ -440,17 +440,24 @@ describe('assert', function () {
 
     err(function () {
       assert.include(42, 'bar');
-    }, "argument of expect() must be an array, an object, or a string, number given");
+    }, "expected 42 to be an array, an object, or a string");
+
+    err(function(){
+      assert.include(null, 42);
+    }, "expected null to be an array, an object, or a string");
 
     err(function () {
       assert.include(undefined, 'bar');
-    }, "argument of expect() must be an array, an object, or a string, undefined given");
+    }, "expected undefined to be an array, an object, or a string");
   });
 
   it('notInclude', function () {
     assert.notInclude('foobar', 'baz');
     assert.notInclude([ 1, 2, 3 ], 4);
-    assert.notInclude(undefined, 'bar');
+
+    err(function () {
+      assert.notInclude(undefined, 'bar');
+    }, "expected undefined to be an array, an object, or a string");
 
     err(function () {
       assert.notInclude('foobar', 'bar');

test/expect.js

@@ -668,7 +668,15 @@ describe('expect', function () {
 
     err(function(){
       expect(42.0).to.include(42);
-    }, "argument of expect() must be an array, an object, or a string, number given");
+    }, "expected 42 to be an array, an object, or a string");
+
+    err(function(){
+      expect(null).to.not.include(42);
+    }, "expected null to be an array, an object, or a string");
+
+    err(function(){
+      expect(undefined).to.not.include(42);
+    }, "expected undefined to be an array, an object, or a string");
   });
 
   it('keys(array|Object|arguments)', function(){

test/should.js

@@ -503,7 +503,7 @@ describe('should', function() {
 
     err(function(){
       (42).should.include(4);
-    }, "argument of expect() must be an array, an object, or a string, number given");
+    }, "expected 42 to be an array, an object, or a string");
   });
 
   it('keys(array|Object|arguments)', function(){