fix python 3 errors

Author: JazzCore

pdfkit/pdfkit.py

@@ -98,18 +98,18 @@ def to_pdf(self, path=None):
         if self.source.isString() or (self.source.isFile() and self.css):
             input = self.source.to_s().encode('utf-8')
         elif self.source.isFileObj():
-            input = self.source.source.read()
+            input = self.source.source.read().encode('utf-8')
         else:
             input = None
         stdout, stderr = result.communicate(input=input)
 
-        if 'Error' in stderr:
-            raise IOError('wkhtmltopdf reported an error:\n' + stderr)
+        if 'Error' in stderr.decode('utf-8'):
+            raise IOError('wkhtmltopdf reported an error:\n' + stderr.decode('utf-8'))
 
         # Since wkhtmltopdf sends its output to stderr we will capture it
         # and properly send to stdout
         if '--quiet' not in args:
-            sys.stdout.write(stderr)
+            sys.stdout.write(stderr.decode('utf-8'))
 
         if not path:
             return stdout

tests/pdfkit-tests.py

@@ -272,7 +272,7 @@ def test_pdf_generation_from_file_like(self):
         with open('fixtures/example.html', 'r') as f:
             r = pdfkit.PDFKit(f, 'file')
             output = r.to_pdf()
-        self.assertEqual(output[:4], '%PDF')
+        self.assertEqual(output[:4].decode('utf-8'), '%PDF')
 
     def test_raise_error_with_wrong_css_path(self):
         css = 'fixtures/wrongpath.css'