Fix.

node_modules/psl/karma.conf.js

@@ -0,0 +1,38 @@
+'use strict';
+
+
+module.exports = function (config) {
+
+  config.set({
+
+    browsers: ['PhantomJS'],
+
+    frameworks: ['browserify', 'mocha'],
+
+    files: [
+      'test/**/*.spec.js'
+    ],
+
+    preprocessors: {
+      'test/**/*.spec.js': ['browserify']
+    },
+
+    reporters: ['mocha'],
+
+    client: {
+      mocha: {
+        reporter: 'tap'
+      }
+    },
+
+    plugins: [
+      'karma-browserify',
+      'karma-mocha',
+      'karma-mocha-reporter',
+      'karma-phantomjs-launcher'
+    ]
+
+  });
+
+};
+