safer version comparisons

@@ -45,7 +45,7 @@ var Mouse = function Mouse(casper) {
 
     var slice = Array.prototype.slice,
         nativeEvents = ['mouseup', 'mousedown', 'click', 'mousemove'];
-    if (phantom.version.major >= 1 && phantom.version.minor >= 8) {
+    if (utils.gteVersion(phantom.version, '1.8.0')) {
         nativeEvents.push('doubleclick');
     }
     var emulatedEvents = ['mouseover', 'mouseout'],

@@ -579,3 +579,59 @@ function unique(array) {
     return r;
 }
 exports.unique = unique;
+
+/**
+ * Compare two version numbers represented as strings.
+ *
+ * @param  String  a  Version a
+ * @param  String  b  Version b
+ * @return Number
+ */
+function cmpVersion(a, b) {
+    var i, cmp, len, re = /(\.0)+[^\.]*$/;
+    function versionToString(version) {
+        if (isObject(version)) {
+            try {
+                return [version.major, version.minor, version.patch].join('.');
+            } catch (e) {}
+        }
+        return version;
+    }
+    a = versionToString(a);
+    b = versionToString(b);
+    a = (a + '').replace(re, '').split('.');
+    b = (b + '').replace(re, '').split('.');
+    len = Math.min(a.length, b.length);
+    for (i = 0; i < len; i++) {
+        cmp = parseInt(a[i], 10) - parseInt(b[i], 10);
+        if (cmp !== 0) {
+            return cmp;
+        }
+    }
+    return a.length - b.length;
+}
+exports.cmpVersion = cmpVersion;
+
+/**
+ * Checks if a version number string is greater or equals another.
+ *
+ * @param  String  a  Version a
+ * @param  String  b  Version b
+ * @return Boolean
+ */
+function gteVersion(a, b) {
+    return cmpVersion(a, b) >= 0;
+}
+exports.gteVersion = gteVersion;
+
+/**
+ * Checks if a version number string is less than another.
+ *
+ * @param  String  a  Version a
+ * @param  String  b  Version b
+ * @return Boolean
+ */
+function ltVersion(a, b) {
+    return cmpVersion(a, b) < 0;
+}
+exports.ltVersion = ltVersion;

 /*global casper*/
 /*jshint strict:false maxstatements: 99*/
+var utils = require('utils');
+
 casper.start('tests/site/index.html', function() {
     this.click('a[href="test.html"]');
 });
@@ -57,7 +59,7 @@ casper.then(function() {
     results = this.getGlobal('results');
     this.test.assertEquals(results.testmove, [200, 100], 'Mouse.move() has moved to the specified position');
 
-    if (phantom.version.major >= 1 && phantom.version.minor >= 8) {
+    if (utils.gteVersion(phantom.version, '1.8.0')) {
         this.test.comment('Mouse.doubleclick()');
         this.mouse.doubleclick(200, 100);
         results = this.getGlobal('results');

 /*jshint strict:false*/
 /*global CasperError casper console phantom require*/
-if (phantom.version.major === 1 && phantom.version.minor < 8) {
+var utils = require('utils')
+
+if (utils.ltVersion(phantom.version, '1.8.0')) {
     // https://github.com/n1k0/casperjs/issues/101
     casper.warn('document.location is broken under phantomjs < 1.8');
     casper.test.done();