Move warning messages to _pytest.deprecated

src/_pytest/deprecated.py

@@ -18,6 +18,22 @@ YIELD_TESTS = RemovedInPytest4Warning(
     "yield tests are deprecated, and scheduled to be removed in pytest 4.0"
 )
 
+CACHED_SETUP = RemovedInPytest4Warning(
+    "cached_setup is deprecated and will be removed in a future release. "
+    "Use standard fixture functions instead."
+)
+
+COMPAT_PROPERTY = (
+    "usage of {owner}.{name} is deprecated, please use pytest.{name} instead"
+)
+
+CUSTOM_CLASS = (
+    'use of special named "{name}" objects in collectors of type "{type_name}" to '
+    "customize the created nodes is deprecated. "
+    "Use pytest_pycollect_makeitem(...) to create custom "
+    "collection nodes instead."
+)
+
 FUNCARG_PREFIX = (
     '{name}: declaring fixtures using "pytest_funcarg__" prefix is deprecated '
     "and scheduled to be removed in pytest 4.0.  "

src/_pytest/fixtures.py

@@ -479,11 +479,9 @@ class FixtureRequest(FuncargnamesCompatAttr):
             or ``session`` indicating the caching lifecycle of the resource.
         :arg extrakey: added to internal caching key of (funcargname, scope).
         """
-        msg = (
-            "cached_setup is deprecated and will be removed in a future release. "
-            "Use standard fixture functions instead."
-        )
-        warnings.warn(RemovedInPytest4Warning(msg), stacklevel=2)
+        from _pytest.deprecated import CACHED_SETUP
+
+        warnings.warn(CACHED_SETUP, stacklevel=2)
         if not hasattr(self.config, "_setupcache"):
             self.config._setupcache = {}  # XXX weakref?
         cachekey = (self.fixturename, self._getscopeitem(scope), extrakey)

src/_pytest/nodes.py

@@ -62,11 +62,12 @@ class _CompatProperty(object):
         if obj is None:
             return self
 
+        from _pytest.deprecated import COMPAT_PROPERTY
+
         warnings.warn(
-            "usage of {owner}.{name} is deprecated, please use pytest.{name} instead".format(
-                name=self.name, owner=owner.__name__
+            RemovedInPytest4Warning(
+                COMPAT_PROPERTY.format(name=self.name, owner=owner.__name__)
             ),
-            RemovedInPytest4Warning,
             stacklevel=2,
         )
         return getattr(__import__("pytest"), self.name)
@@ -129,14 +130,14 @@ class Node(object):
         if isinstance(maybe_compatprop, _CompatProperty):
             return getattr(__import__("pytest"), name)
         else:
+            from _pytest.deprecated import CUSTOM_CLASS
+
             cls = getattr(self, name)
-            msg = (
-                'use of special named "%s" objects in collectors of type "%s" to '
-                "customize the created nodes is deprecated. "
-                "Use pytest_pycollect_makeitem(...) to create custom "
-                "collection nodes instead." % (name, type(self).__name__)
+            self.warn(
+                RemovedInPytest4Warning(
+                    CUSTOM_CLASS.format(name=name, type_name=type(self).__name__)
+                )
             )
-            self.warn(RemovedInPytest4Warning(msg))
         return cls
 
     def __repr__(self):