test(render-files): cover with tests render-files

lib/render-files.spec.js

@@ -1,2 +1,20 @@
 'use strict'
-require('./render-files')
+const describe = require('mocha').describe
+const it = require('mocha').it
+const renderFiles = require('./render-files')
+const path = require('path')
+
+describe('render-files', () => {
+  it('should render files by pattern', done => {
+    renderFiles({
+      pattern: path.join(__dirname, '/test-cli/*.md'),
+      processor: {
+        process: () => Promise.resolve(),
+      },
+      afterEachRender: () => {},
+      ignorePattern: 'ignore_this_path',
+    })
+    .then(() => done())
+    .catch(done)
+  })
+})