re-enable the standalone-mss rendering tests and fix them by avoiding…

… empty styles and empty rules - closes less#219

lib/carto/renderer.js

@@ -47,7 +47,7 @@ carto.Renderer.prototype.renderMSS = function render(data, callback) {
  if (env.benchmark) console.time('Total Style generation');
  for (var k = 0, rule, style_name; k < sorted.length; k++) {
  rule = sorted[k];
- style_name = 'style-' + (rule.attachment !== '__default__' ? '-' + rule.attachment : '');
+ style_name = 'style' + (rule.attachment !== '__default__' ? '-' + rule.attachment : '');
  styles.push(style_name);
  var bench_name = '\tStyle "'+style_name+'" (#'+k+') toXML';
  if (env.benchmark) console.time(bench_name);

lib/carto/tree/definition.js

@@ -81,8 +81,7 @@ function symbolizerList(sym_order) {
 }
 
 tree.Definition.prototype.symbolizersToXML = function(env, symbolizers, zoom) {
- var xml = ' <Rule>\n' + zoom.toXML(env).join('') +
- this.filters.toXML(env);
+ var xml = zoom.toXML(env).join('') + this.filters.toXML(env);
 
  // Sort symbolizers by the index of their first property definition
  var sym_order = [], indexes = [];
@@ -143,8 +142,8 @@ tree.Definition.prototype.symbolizersToXML = function(env, symbolizers, zoom) {
  }
  }
  }
- xml += ' </Rule>\n';
- return xml;
+ if (!xml) return '';
+ return ' <Rule>\n' + xml + ' </Rule>\n';
 };
 
 // Take a zoom range of zooms and 'i', the index of a rule in this.rules,

lib/carto/tree/style.js

@@ -38,8 +38,9 @@ tree.Style.toXML = function(name, attachment, definitions, env) {
  if (opacity.length) {
  attrs_xml += ' opacity="' + opacity[0].value.eval(env).toString() + '" ';
  }
-
- return '<Style name="' + name + '" filter-mode="first" ' + attrs_xml + '>\n' + rules.join('') + '</Style>';
+ var rule_string = rules.join('');
+ if (!attrs_xml && !rule_string) return '';
+ return '<Style name="' + name + '" filter-mode="first" ' + attrs_xml + '>\n' + rule_string + '</Style>';
 };
 
 })(require('../tree'));

test/rendering-mss.test.js

@@ -7,7 +7,7 @@ var carto = require('../lib/carto');
 var tree = require('../lib/carto/tree');
 var helper = require('./support/helper');
 
-/*
+
 
 describe('Rendering mss', function() {
 helper.files('rendering-mss', 'mss', function(file) {
@@ -43,4 +43,3 @@ helper.files('rendering-mss', 'mss', function(file) {
 });
 });
 
-*/

test/rendering-mss/should-discard-empty-style-and-attach.xml

@@ -0,0 +1 @@
+