Ajax: Ensure ajaxSettings.traditional is still honored

Fixes jquerygh-3023
Closes jquerygh-3081

Since .param() no longer looks at this setting we need unit tests
to ensure it is still honored by $.ajax().

test/unit/ajax.js

@@ -373,6 +373,64 @@ QUnit.module( "ajax", {
 		];
 	} );
 
+	ajaxTest( "jQuery.ajax() - traditional param encoding", 4, function( assert ) {
+		return [
+			{
+				url: "/",
+				traditional: true,
+				data: {
+					"devo": "hat",
+					"answer": 42,
+					"quux": "a space"
+				},
+				beforeSend: function( xhr, settings ) {
+					assert.equal( settings.url, "/?devo=hat&answer=42&quux=a%20space", "Simple case" );
+					return false;
+				},
+				error: true
+			},
+			{
+				url: "/",
+				traditional: true,
+				data: {
+					"a": [ 1, 2, 3 ],
+					"b[]": [ "b1", "b2" ]
+				},
+				beforeSend: function( xhr, settings ) {
+					assert.equal( settings.url, "/?a=1&a=2&a=3&b%5B%5D=b1&b%5B%5D=b2", "Arrays" );
+					return false;
+				},
+				error: true
+			},
+			{
+				url: "/",
+				traditional: true,
+				data: {
+					"a": [ [ 1, 2 ], [ 3, 4 ], 5 ]
+				},
+				beforeSend: function( xhr, settings ) {
+					assert.equal( settings.url, "/?a=1%2C2&a=3%2C4&a=5", "Nested arrays" );
+					return false;
+				},
+				error: true
+			},
+			{
+				url: "/",
+				traditional: true,
+				data: {
+					"a": [ "w", [ [ "x", "y" ], "z" ] ]
+				},
+				cache: false,
+				beforeSend: function( xhr, settings ) {
+					var url = settings.url.replace( /\d{3,}/, "" );
+					assert.equal( url, "/?a=w&a=x%2Cy%2Cz&_=", "Cache-buster" );
+					return false;
+				},
+				error: true
+			}
+		];
+	} );
+
 	ajaxTest( "jQuery.ajax() - cross-domain detection", 8, function( assert ) {
 		function request( url, title, crossDomainOrOptions ) {
 			return jQuery.extend( {

test/unit/serialize.js

@@ -1,7 +1,7 @@
 QUnit.module( "serialize", { teardown: moduleTeardown } );
 
 QUnit.test( "jQuery.param()", function( assert ) {
-	assert.expect( 24 );
+	assert.expect( 23 );
 
 	var params;
 
@@ -56,7 +56,7 @@ QUnit.test( "jQuery.param()", function( assert ) {
 	assert.equal( jQuery.param( params, true ), "a=1&a=2&b=%5Bobject%20Object%5D&i=10&i=11&j=true&k=false&l=&l=0&m=cowboy%20hat%3F", "huge structure" );
 
 	params = { "a": [ 0, [ 1, 2 ], [ 3, [ 4, 5 ], [ 6 ] ], { "b": [ 7, [ 8, 9 ], [ { "c": 10, d: 11 } ], [ [ 12 ] ], [ [ [ 13 ] ] ], { "e": { "f": { "g": [ 14, [ 15 ] ] } } }, 16 ] }, 17 ] };
-	assert.equal( jQuery.param( params, true ), "a=0&a=1%2C2&a=3%2C4%2C5%2C6&a=%5Bobject%20Object%5D&a=17", "nested arrays (not possible when jQuery.param.traditional == true)" );
+	assert.equal( jQuery.param( params, true ), "a=0&a=1%2C2&a=3%2C4%2C5%2C6&a=%5Bobject%20Object%5D&a=17", "nested arrays (not possible when traditional == true)" );
 
 	params = { a:[ 1,2 ], b:{ c:3, d:[ 4,5 ], e:{ x:[ 6 ], y:7, z:[ 8,9 ] }, f:true, g:false, h:undefined }, i:[ 10,11 ], j:true, k:false, l:[ undefined,0 ], m:"cowboy hat?" };
 	assert.equal( decodeURIComponent( jQuery.param( params ) ), "a[]=1&a[]=2&b[c]=3&b[d][]=4&b[d][]=5&b[e][x][]=6&b[e][y]=7&b[e][z][]=8&b[e][z][]=9&b[f]=true&b[g]=false&b[h]=&i[]=10&i[]=11&j=true&k=false&l[]=&l[]=0&m=cowboy hat?", "huge structure, forced not traditional" );
@@ -74,6 +74,19 @@ QUnit.test( "jQuery.param()", function( assert ) {
 	assert.equal( jQuery.param( params ), "test%5B%5D=1&test%5B%5D=2&test%5B%5D=", "object with array property with null value" );
 } );
 
+QUnit.test( "jQuery.param() not affected by ajaxSettings", function( assert ) {
+	assert.expect( 1 );
+
+	var oldTraditional = jQuery.ajaxSettings.traditional;
+	jQuery.ajaxSettings.traditional = true;
+	assert.equal(
+		jQuery.param( { "foo": [ "a", "b", "c" ] } ),
+		"foo%5B%5D=a&foo%5B%5D=b&foo%5B%5D=c",
+		"ajaxSettings.traditional is ignored"
+	);
+	jQuery.ajaxSettings.traditional = oldTraditional;
+} );
+
 QUnit.test( "jQuery.param() Constructed prop values", function( assert ) {
 	assert.expect( 4 );