first test and fixes for simple implementation

Author: lukeapage

lib/less/import-visitor.js

@@ -39,11 +39,11 @@
         visitMixinDefinitionOut: function (mixinDefinitionNode) {
             this.env.frames.shift();
         },
-        visitRulesetDefinition: function (rulesetNode, visitArgs) {
+        visitRuleset: function (rulesetNode, visitArgs) {
             this.env.frames.unshift(rulesetNode);
             return rulesetNode;
         },
-        visitRulesetDefinitionOut: function (rulesetNode) {
+        visitRulesetOut: function (rulesetNode) {
             this.env.frames.shift();
         },
         visitMedia: function (mediaNode, visitArgs) {

lib/less/parser.js

@@ -468,7 +468,12 @@ less.Parser = function Parser(env) {
                 };
             }
 
-            new tree.importVisitor(root, parser.imports);
+            try {
+                new tree.importVisitor(root, parser.imports);
+            }
+            catch(e) {
+                error = e;
+            }
 
             finish = function (e) {
                 e = error || e || parser.imports.error;

test/css/import-interpolation.css

@@ -0,0 +1,3 @@
+body {
+  width: 100%;
+}

test/less/import-interpolation.less

@@ -0,0 +1,3 @@
+@my_theme: "test";
+
+@import "import/import-@{my_theme}-e.less";