feat: support relative serverless config

Author: Eric Czajkowski

lib/yamlParser.test.js

@@ -2,6 +2,7 @@
 
 const expect = require('chai').expect;
 const sinon = require('sinon');
+const path = require('path');
 const BbPromise = require('bluebird');
 const Serverless = require('serverless/lib/Serverless');
 const AwsProvider = require('serverless/lib/plugins/aws/provider/awsProvider');
@@ -154,6 +155,17 @@ describe('#yamlParse', () => {
           expect(yamlParserStub.calledWith(`${servicePath}/${fileName}`)).to.be.equal(true);
         });
     });
+
+    it('should read relative serviceFileName path if passed as --config option', () => {
+      const servicePath = serverlessStepFunctions.serverless.config.servicePath;
+      const relativeFilename = './some_folder/other_config.yml';
+      serverlessStepFunctions.options.config = relativeFilename;
+      const serviceFilePath = path.normalize(`${servicePath}/${relativeFilename}`);
+      serverlessStepFunctions.yamlParse()
+        .then(() => {
+          expect(yamlParserStub.calledWith(serviceFilePath)).to.be.equal(true);
+        });
+    });
   });
 
   describe('#getAllStateMachines()', () => {