fixed #281 - Casper.evaluate() method signature

`Casper.evaluate()` method signature is now compatible with PhantomJS' one, so you can now write:

```js
casper.evaluate(function(a, b) {
    return a === "foo" && b === "bar";
}, "foo", "bar"); // true
```

The old way to pass arguments has been kept backward compatible in order not to break your existing scripts though:

```js
casper.evaluate(function(a, b) {
    return a === "foo" && b === "bar";
}, {a: "foo", b: "bar"}); // true
```

@@ -4,13 +4,34 @@ CasperJS Changelog
 XXXX-XX-XX, v1.0.0
 ------------------
 
-- fixed `Casper.die()` and `Casper.evaluateOrDie()` were not printing the error onto the console
+### Important Changes & Caveats
+
+`Casper.evaluate()` method signature is now compatible with PhantomJS' one, so you can now write:
+
+```js
+casper.evaluate(function(a, b) {
+    return a === "foo" && b === "bar";
+}, "foo", "bar"); // true
+```
+
+The old way to pass arguments has been kept backward compatible in order not to break your existing scripts though:
+
+```js
+casper.evaluate(function(a, b) {
+    return a === "foo" && b === "bar";
+}, {a: "foo", b: "bar"}); // true
+```
+
+### Bugfixes & enhancements
+
+- fixed [#281](https://github.com/n1k0/casperjs/issues/281) - `Casper.evaluate()` should take an array as context not object
 - fixed [#266](https://github.com/n1k0/casperjs/issues/266) - Fix `tester` module and its self tests
 - fixed [#268](https://github.com/n1k0/casperjs/issues/266) - Wrong message on step timeout
 - fixed [#215](https://github.com/n1k0/casperjs/issues/215) - added a `--fail-fast` option to the `casper test` command, in order to terminate a test suite execution as soon as any failure is encountered
 - fixed [#274](https://github.com/n1k0/casperjs/issues/274) - some headers couldn't be set
 - fixed [#277](https://github.com/n1k0/casperjs/issues/277) - multiline support in `ClientUtils.echo()`
 - fixed [#282](https://github.com/n1k0/casperjs/issues/282) - added support for remote client scripts loading with a new `remoteScripts` casper option
+- fixed `Casper.die()` and `Casper.evaluateOrDie()` were not printing the error onto the console
 - added [`Tester.assertTextDoesntExist()`](http://casperjs.org/api.html#tester.assertTextDoesntExist)
 - added `Tester.assertFalse()` as an alias of `Tester.assertNot()`
 - added `page.resource.requested` and `page.resource.received` events

-Subproject commit e15667bcfb7e76b057212f3c2337cee0a39e793e
+Subproject commit 7407e89f51ffa7c95f85c017654a82de86239a17

@@ -603,12 +603,27 @@ Casper.prototype.evaluate = function evaluate(fn, context) {
     // ensure client utils are always injected
     this.injectClientUtils();
     // function context
-    context = utils.isObject(context) ? context : {};
-    // the way this works is kept for BC with older casperjs versions
-    var args = Object.keys(context).map(function(arg) {
-        return context[arg];
-    });
-    return this.page.evaluate.apply(this.page, [fn].concat(args));
+    if (arguments.length === 1) {
+        return this.page.evaluate(fn);
+    } else if (arguments.length === 2) {
+        // check for closure signature if it matches context
+        if (utils.isObject(context) && eval(fn).length === Object.keys(context).length) {
+            context = Object.keys(context).map(function(arg) {
+                return context[arg];
+            });
+        } else {
+            context = [context];
+        }
+    } else if (arguments.length > 2) {
+        // phantomjs-style signature
+        context = [].slice.call(arguments).slice(1);
+    } else {
+        // old casperjs method signature
+        context = Object.keys(context).map(function(arg) {
+            return context[arg];
+        });
+    }
+    return this.page.evaluate.apply(this.page, [fn].concat(context));
 };
 
 /**

 /*global casper*/
-/*jshint strict:false maxparams:99*/
+/*jshint strict:false*/
 casper.test.comment('Casper.evaluate()');
 
 casper.start();
@@ -32,4 +32,42 @@ casper.test.assertEquals(result.toString(),
                          ['boolean', 'boolean', 'number', 'number', 'string', 'object', 'object', 'function'].toString(),
                          'Casper.evaluate() handles passed argument context correcly');
 
+// no context
+casper.test.assertEquals(casper.evaluate(function() {
+    return 42;
+}), 42, 'Casper.evaluate() handles evaluation with no context passed');
+
+// object context (previous casperjs versions compatibility mode)
+casper.test.assertEquals(casper.evaluate(function(a) {
+    return [a];
+}, {a: "foo"}), ["foo"], 'Casper.evaluate() accepts an object as arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b) {
+    return [a, b];
+}, {a: "foo", b: "bar"}), ["foo", "bar"], 'Casper.evaluate() accepts an object as arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b, c) {
+    return [a, b, c];
+}, {a: "foo", b: "bar", c: "baz"}), ["foo", "bar", "baz"], 'Casper.evaluate() accepts an object as arguments context');
+
+// array context
+casper.test.assertEquals(casper.evaluate(function(a) {
+    return [a];
+}, ["foo"]), ["foo"], 'Casper.evaluate() accepts an array as arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b) {
+    return [a, b];
+}, ["foo", "bar"]), ["foo", "bar"], 'Casper.evaluate() accepts an array as arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b, c) {
+    return [a, b, c];
+}, ["foo", "bar", "baz"]), ["foo", "bar", "baz"], 'Casper.evaluate() accepts an array as arguments context');
+
+// natural arguments context (phantomjs equivalent)
+casper.test.assertEquals(casper.evaluate(function(a) {
+    return [a];
+}, "foo"), ["foo"], 'Casper.evaluate() accepts natural arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b) {
+    return [a, b];
+}, "foo", "bar"), ["foo", "bar"], 'Casper.evaluate() accepts natural arguments context');
+casper.test.assertEquals(casper.evaluate(function(a, b, c) {
+    return [a, b, c];
+}, "foo", "bar", "baz"), ["foo", "bar", "baz"], 'Casper.evaluate() accepts natural arguments context');
+
 casper.test.done();