Better test failure information

engine.js

@@ -16,9 +16,11 @@ function Engine (name, fn) {
 
     exports.bench = function (css, precise) {
         var start = process.hrtime();
-        return new Promise(function (resolve) {
-            return Promise.resolve(fn(css)).then(function () {
+        return new Promise(function (resolve, reject) {
+            Promise.resolve(fn(css)).then(function () {
                 resolve(pretty(process.hrtime(start), {precise: precise}));
+            }, function (err) {
+                reject(err);
             });
         });
     };

engines/more-css.js

@@ -5,10 +5,14 @@ var more = require('more-css');
 
 module.exports = new Engine('more-css', function (css) {
     return new Promise(function (resolve, reject) {
-        var minified = more.compress(css, true);
-        if (minified.indexOf('Error: ') === 0) {
-            return reject(new Error(minified));
+        try {
+            var minified = more.compress(css, true);
+            if (minified.indexOf('Error: ') === 0) {
+                return reject(new Error(minified));
+            }
+            return resolve(minified);
+        } catch (e) {
+            reject(e);
         }
-        return resolve(minified);
     });
 });

test.js

@@ -12,6 +12,8 @@ test('integration tests', function (t) {
     Object.keys(minifiers).forEach(function (minifier) {
         Promise.resolve(minifiers[minifier](css)).then(function (css) {
             t.equal(css, expected, 'should minify css with ' + minifier);
+        }, function (err) {
+            t.fail('Failure from engine "' + minifier + '": ' + String(err));
         });
     });
 });
@@ -23,6 +25,8 @@ test('benchmark tests', function (t) {
         var minifier = minifiers[m];
         Promise.resolve(minifier.bench(css)).then(function (time) {
             t.ok(time, minifier + ' took ' + time);
+        }, function (err) {
+            t.fail('Failure from engine "' + minifier + '": ' + String(err));
         });
     });
 });