Ensure printable manually-specified param(id=...)

src/_pytest/mark/structures.py

@@ -8,6 +8,7 @@ import attr
 import six
 from six.moves import map
 
+from ..compat import ascii_escaped
 from ..compat import getfslineno
 from ..compat import MappingMixin
 from ..compat import NOTSET
@@ -77,6 +78,7 @@ class ParameterSet(namedtuple("ParameterSet", "values, marks, id")):
                 raise TypeError(
                     "Expected id to be a string, got {}: {!r}".format(type(id_), id_)
                 )
+            id_ = ascii_escaped(id_)
         return cls(values, marks, id_)
 
     @classmethod