catch template syntax errors

Rendering a template with syntax errors throws. Catch this and call the
callback to pass the error along to the error handling middleware.

Add tests to check for proper handling of the error.

fixes pillarjs#35

lib/hbs.js

@@ -57,14 +57,19 @@ exports.__express = function(filename, options, cb) {
         cache[filename] = template;
       }
 
-      var res = template(locals);
-      async.done(function(values) {
-        Object.keys(values).forEach(function(id) {
-          res = res.replace(id, values[id]);
+      try {
+        var res = template(locals);
+        async.done(function(values) {
+          Object.keys(values).forEach(function(id) {
+            res = res.replace(id, values[id]);
+          });
+
+          cb(null, res);
         });
-
-        cb(null, res);
-      });
+      } catch (err) {
+        err.message = filename + ': ' + err.message;
+        cb(err);
+      }
     });
   }
 

test/2.x/app.js

@@ -74,6 +74,10 @@ app.get('/', function(req, res){
   });
 });
 
+app.get('/syntax-error', function(req, res) {
+  res.render('syntax-error');
+});
+
 test('index', function(done) {
   app.listen(3000, function() {
 
@@ -85,7 +89,22 @@ test('index', function(done) {
     });
   });
 
-  app.on('close', function() {
+  app.once('close', function() {
+    done();
+  });
+});
+
+test('syntax error', function(done) {
+  app.listen(3000, function() {
+
+    request('http://localhost:3000/syntax-error', function(err, res, body) {
+      assert.equal(res.statusCode, 500);
+      assert.equal(body.split('\n')[0], 'Error: Parse error on line 1:');
+      app.close();
+    });
+  });
+
+  app.once('close', function() {
     done();
   });
 });

test/2.x/views/syntax-error.hbs

@@ -0,0 +1 @@
+{{foo}

test/3.x/app.js

@@ -111,6 +111,10 @@ app.get('/html', function(req, res) {
   });
 });
 
+app.get('/syntax-error', function(req, res) {
+  res.render('syntax-error');
+});
+
 test('index', function(done) {
   var server = app.listen(3000, function() {
 
@@ -142,3 +146,19 @@ test('html extension', function(done) {
     done();
   });
 });
+
+test('syntax error', function(done) {
+  var server = app.listen(3000, function() {
+
+    request('http://localhost:3000/syntax-error', function(err, res, body) {
+      assert.equal(res.statusCode, 500);
+      assert.equal(body.split('\n')[0], 'Error: ' + __dirname + '/views/syntax-error.hbs: Parse error on line 1:');
+      //assert.equal(bod);
+      server.close();
+    });
+  });
+
+  server.on('close', function() {
+    done();
+  });
+});

test/3.x/views/syntax-error.hbs

@@ -0,0 +1 @@
+{{foo}