Update test fixtures and plugin utils for buidler plugin

dist/plugin-assets/truffle.utils.js

@@ -183,6 +183,7 @@ function loadLibrary(config){
 
 }
 
+
 /**
  * Maps truffle specific keys for the paths to things like sources to the generic
  * keys required by the plugin utils
@@ -197,6 +198,7 @@ function normalizeConfig(config){
   return config;
 }
 
+
 module.exports = {
   getTestFilePaths: getTestFilePaths,
   setNetwork: setNetwork,

dist/truffle.plugin.js

@@ -124,4 +124,18 @@ async function plugin(config){
   if (failures > 0) throw new Error(ui.generate('tests-fail', [failures]));
 }
 
+/**
+ * Maps truffle specific keys for the paths to things like sources to the generic
+ * keys required by the plugin utils
+ * @return {Object} truffle-config.js
+ */
+function normalizeConfig(config){
+  config.workingDir = config.working_directory;
+  config.contractsDir = config.contracts_directory;
+  config.testDir = config.test_directory;
+  config.artifactsDir = config.build_directory;
+
+  return config;
+}
+
 module.exports = plugin;