--- contrib/python/pytest/py2/_pytest/compat.py	(index)
+++ contrib/python/pytest/py2/_pytest/compat.py	(working tree)
@@ -378,7 +378,10 @@ if _PY3:
 
     def safe_str(v):
         """returns v as string"""
-        return str(v)
+        try:
+            return str(v)
+        except UnicodeEncodeError:
+            return str(v, encoding="utf-8")
 
 
 else:
--- contrib/python/pytest/py2/_pytest/python.py	(index)
+++ contrib/python/pytest/py2/_pytest/python.py	(working tree)
@@ -896,7 +896,7 @@ class CallSpec2(object):
 
     @property
     def id(self):
-        return "-".join(map(str, filter(None, self._idlist)))
+        return "-".join(map(safe_str, filter(None, self._idlist)))
 
     def setmulti2(self, valtypes, argnames, valset, id, marks, scopenum, param_index):
         for arg, val in zip(argnames, valset):
@@ -1218,10 +1218,10 @@ def limit_idval(limit):
             if len(idval) > limit:
                 prefix = idval[:limit]
                 # There might be same prefix for the different test cases - take item into account
-                name = "{}-{}".format(kw.get('item', ''), prefix)
+                name = "{}-{}".format(kw.get('item', ''), safe_str(prefix))
                 idx = names.setdefault(name, -1) + 1
                 names[name] = idx
-                idval = "{}-{}".format(prefix, idx)
+                idval = "{}-{}".format(safe_str(prefix), idx)
             return idval
 
         return wrapper
--- contrib/python/pytest/py2/_pytest/runner.py	(index)
+++ contrib/python/pytest/py2/_pytest/runner.py	(working tree)
@@ -16,6 +16,7 @@ from .reports import CollectErrorRepr
 from .reports import CollectReport
 from .reports import TestReport
 from _pytest._code.code import ExceptionInfo
+from _pytest.compat import safe_str
 from _pytest.outcomes import Exit
 from _pytest.outcomes import Skipped
 from _pytest.outcomes import TEST_OUTCOME
@@ -241,7 +242,7 @@ class CallInfo(object):
             value = repr(self._result)
             status = "result"
         return "<CallInfo when={when!r} {status}: {value}>".format(
-            when=self.when, value=value, status=status
+            when=self.when, value=safe_str(value), status=status
         )