fixed build fail where karama.conf.js is not present

Author: benholloway

lib/test/karma.js

@@ -137,15 +137,17 @@ function karmaCreateConfig(reporters, configFileName) {
       return JSON.stringify(value, null, 2).replace(/\"/g, '\'');
     }
     var filePath = path.resolve(configFileName);
-    var contents = fs.readFileSync(filePath).toString()
-      .replace(basePathRegex,        encode(process.cwd()))
-      .replace(filesAppendRegex,     encode(files.concat(additional)))
-      .replace(reportersAppendRegex, encode(reporters.map(getKarmaReporterName)))
-      .replace(pluginsAppendRegex,   '[\n' + reporters.map(requirePlugins).join(',\n') + '\n]');
-    this.push(new gutil.File({
-      path    : filePath,
-      contents: new Buffer(contents)
-    }));
+    if (fs.existsSync(filePath)) {
+      var contents = fs.readFileSync(filePath).toString()
+        .replace(basePathRegex,        encode(process.cwd()))
+        .replace(filesAppendRegex,     encode(files.concat(additional)))
+        .replace(reportersAppendRegex, encode(reporters.map(getKarmaReporterName)))
+        .replace(pluginsAppendRegex,   '[\n' + reporters.map(requirePlugins).join(',\n') + '\n]');
+      this.push(new gutil.File({
+        path    : filePath,
+        contents: new Buffer(contents)
+      }));
+    }
     done();
   }
   return through.obj(transformFn, flushFn);