new_contents: from . import IpynbTest, RmdTest
  
  yaml_source = """---
  title: Test document
  author: foobar <foo@bar.tld>
  date: 1970-01-01T00:00:00+0000
  output:
      html_document:
          toc: true
  ünicode: £¼±å
  ---
  lorem ipsum
  ```{r}
  1+1
  ```
  """
  class TestYAMLHeader(RmdTest):
      source = yaml_source
  
      def test_header_in_ipynb(self):
          self.assertIn("Rmd_header", self.ipynb.metadata)
          header = self.ipynb.metadata.Rmd_header
          self.assertIn("title", header)
          self.assertIn("author", header)
          self.assertIn("date", header)
          self.assertIn("output", header)
          self.assertIn("ünicode", header)
          self.assertEqual("Test document", header.title)
          self.assertEqual("foobar <foo@bar.tld>", header.author)
          self.assertEqual("1970-01-01T00:00:00+0000", header.date)
          self.assertEqual(True, header.output.html_document.toc)
          self.assertEqual("£¼±å", header.ünicode)
  
  
      def test_header_in_rmd(self):
          self.assertIn("---", self.roundtrip)
          self.assertIn("Test document", self.roundtrip)
          self.assertIn("foobar <foo@bar.tld>", self.roundtrip)
          self.assertIn("1970-01-01T00:00:00+0000", self.roundtrip)
          self.assertIn("£¼±å", self.roundtrip)
          self.assertRegexpMatches(self.roundtrip, r"output:\s*html_document:\s*toc:\s*true")
          self.assertIn("1+1", self.roundtrip)
          self.assertIn("lorem ipsum", self.roundtrip)
  
  spin_yaml_source = """#' ---
  #' title: Test document
  #' author: foobar <foo@bar.tld>
  #' date: 1970-01-01T00:00:00+0000
  #' output:
  #'     html_document:
  #'         toc: true
  #' ünicode: £¼±å
  #' ---
  #' lorem ipsum
  1+1
  """
  class TestSpinYAMLHeader(TestYAMLHeader):
      source = spin_yaml_source
      use_rmd = False
  
subject: Add some tests for yaml header handling