migrated casper/capture tests to new testing format

 /*global casper*/
 /*jshint strict:false*/
-var fs = require('fs'), testFile = '/tmp/__casper_test_capture.png';
+var fs = require('fs'),
+    testFile = '/tmp/__casper_test_capture.png';
 
 if (fs.exists(testFile) && fs.isFile(testFile)) {
     fs.remove(testFile);
 }
 
-casper.start('tests/site/index.html', function() {
-    this.viewport(300, 200);
-    this.test.comment('Casper.capture()');
-    this.capture(testFile);
-    this.test.assert(fs.isFile(testFile), 'Casper.capture() captured a screenshot');
+casper.test.begin('Casper.capture() tests', 1, function(test) {
+    casper.start('tests/site/index.html', function() {
+        this.viewport(300, 200);
+        this.capture(testFile);
+        test.assert(fs.isFile(testFile), 'Casper.capture() captured a screenshot');
+    }).run(function() {
+        try {
+            fs.remove(testFile);
+        } catch(e) {
+            this.warn('Unable to delete test file ' + testFile + '; please delete it manually');
+        }
+        test.done();
+    });
 });
 
-casper.thenOpen('tests/site/index.html', function() {
-    this.test.comment('Casper.captureBase64()');
-    this.test.assert(this.captureBase64('png').length > 0,
-                     'Casper.captureBase64() rendered a page capture as base64');
-    this.test.assert(this.captureBase64('png', 'ul').length > 0,
-                     'Casper.captureBase64() rendered a capture from a selector as base64');
-    this.test.assert(this.captureBase64('png', {top: 0, left: 0, width: 30, height: 30}).length > 0,
-                     'Casper.captureBase64() rendered a capture from a clipRect as base64');
-});
-
-casper.run(function() {
-    try {
-        fs.remove(testFile);
-    } catch(e) {}
-    this.test.done(4);
+casper.test.begin('Casper.captureBase64() tests', 3, function(test) {
+    casper.start('tests/site/index.html', function() {
+        test.assert(this.captureBase64('png').length > 0,
+                         'Casper.captureBase64() rendered a page capture as base64');
+        test.assert(this.captureBase64('png', 'ul').length > 0,
+                         'Casper.captureBase64() rendered a capture from a selector as base64');
+        test.assert(this.captureBase64('png', {top: 0, left: 0, width: 30, height: 30}).length > 0,
+                         'Casper.captureBase64() rendered a capture from a clipRect as base64');
+    }).run(function() {
+        test.done();
+    });
 });