test: for source, issue #243

test/source.js

@@ -0,0 +1,36 @@
+var it = require('mocha').it
+var expect = require('chai').expect
+var describe = require('mocha').describe
+
+var posthtml = require('../lib')
+
+var html = '<div class="source">source</div>'
+var expected = '<div>source</div>'
+
+function test (html, done) {
+  posthtml()
+    .use(function (tree) {
+      return tree.walk(node => {
+        if (node.attrs) {
+          delete node.attrs.class
+        }
+
+        return node
+      })
+    })
+    .process(html)
+    .then(function (result) {
+      expect(html).to.eql(result.tree.source)
+      expect(expected).to.eql(result.html)
+      done()
+    })
+    .catch(function (error) {
+      done(error)
+    })
+}
+
+describe('Source', function () {
+  it('Source code must not mutate', function (done) {
+    test(html, done)
+  })
+})