if reading from source returns bytes do utf-8 decoding

don’t pass StringIO returning decoded unicode to Result parser

rdflib/plugins/sparql/results/csvresults.py

@@ -23,7 +23,8 @@ def parse(self, source):
 
         r = Result('SELECT')
 
-        if hasattr(source, 'mode') and 'b' in source.mode:
+        if isinstance(source.read(0), py3compat.bytestype):
+            # if reading from source returns bytes do utf-8 decoding
             source = codecs.getreader('utf-8')(source)
 
         reader = csv.reader(source, delimiter=self.delim)

rdflib/plugins/sparql/results/tsvresults.py

@@ -19,6 +19,8 @@
 
 from rdflib import Literal as RDFLiteral
 
+from rdflib.py3compat import bytestype
+
 ParserElement.setDefaultWhitespaceChars(" \n")
 
 
@@ -40,7 +42,8 @@
 class TSVResultParser(ResultParser):
     def parse(self, source):
 
-        if hasattr(source, 'mode') and 'b' in source.mode:
+        if isinstance(source.read(0), bytestype):
+            # if reading from source returns bytes do utf-8 decoding
             source = codecs.getreader('utf-8')(source)
 
         try:

test/test_dawg.py

@@ -391,8 +391,7 @@ def skip(reason='(none)'):
             # write bytes, read strings...
             s = BytesIO()
             res2.serialize(s, format='csv')
-            print s.getvalue()
-            s = StringIO(s.getvalue().decode('utf-8'))  # hmm ?
+            s.seek(0)
             res2 = Result.parse(s, format='csv')
 
         else: