* xspec: define str(xspec) to give back the original specification string

* fix a test invocation

--HG--
branch : trunk

py/execnet/testing/test_xspec.py

@@ -36,9 +36,10 @@ class TestXSpec:
         for x in ("popen", "popen//python=this"):
             assert XSpec(x)._spec == x
 
-    def test_repr(self):
+    def test_repr_and_string(self):
         for x in ("popen", "popen//python=this"):
             assert repr(XSpec(x)).find("popen") != -1
+            assert str(XSpec(x)) == x
 
     def test_hash_equality(self):
         assert XSpec("popen") == XSpec("popen")