diff --git a/mitogen/parent.py b/mitogen/parent.py
index e2c22110..d8485e15 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -339,7 +339,7 @@ def iter_read(fds, deadline=None):
 
     if not poller.readers:
         raise mitogen.core.StreamError(
-            'EOF on stream; last 300 bytes received: %r' %
+            u'EOF on stream; last 300 bytes received: %r' %
             (b('').join(bits)[-300:].decode('latin1'),)
         )
     raise mitogen.core.TimeoutError('read timed out')
diff --git a/tests/parent_test.py b/tests/parent_test.py
index 31c168e9..06eac97e 100644
--- a/tests/parent_test.py
+++ b/tests/parent_test.py
@@ -57,7 +57,8 @@ class StreamErrorTest(testlib.RouterMixin, testlib.TestCase):
                 connect_timeout=3,
             )
         )
-        self.assertEquals(e.args[0], "EOF on stream; last 300 bytes received: ''")
+        prefix = "EOF on stream; last 300 bytes received: "
+        self.assertTrue(e.args[0].startswith(prefix))
 
     def test_via_eof(self):
         # Verify FD leakage does not keep failed process open.
@@ -69,7 +70,8 @@ class StreamErrorTest(testlib.RouterMixin, testlib.TestCase):
                 connect_timeout=3,
             )
         )
-        self.assertTrue("EOF on stream; last 300 bytes received: ''" in e.args[0])
+        s = "EOF on stream; last 300 bytes received: "
+        self.assertTrue(s in e.args[0])
 
     def test_direct_enoent(self):
         e = self.assertRaises(mitogen.core.StreamError,