Change std_warn to receive a single warning instance, addressed review suggestions

src/_pytest/config/__init__.py

@@ -154,7 +154,7 @@ def get_plugin_manager():
 
 
 def _prepareconfig(args=None, plugins=None):
-    warning_msg = None
+    warning = None
     if args is None:
         args = sys.argv[1:]
     elif isinstance(args, py.path.local):
@@ -165,7 +165,7 @@ def _prepareconfig(args=None, plugins=None):
         args = shlex.split(args, posix=sys.platform != "win32")
         from _pytest import deprecated
 
-        warning_msg = deprecated.MAIN_STR_ARGS
+        warning = deprecated.MAIN_STR_ARGS
     config = get_config()
     pluginmanager = config.pluginmanager
     try:
@@ -175,11 +175,10 @@ def _prepareconfig(args=None, plugins=None):
                     pluginmanager.consider_pluginarg(plugin)
                 else:
                     pluginmanager.register(plugin)
-        if warning_msg:
+        if warning:
-            from _pytest.warning_types import PytestWarning
             from _pytest.warnings import _issue_config_warning
 
-            _issue_config_warning(PytestWarning(warning_msg), config=config)
+            _issue_config_warning(warning, config=config)
         return pluginmanager.hook.pytest_cmdline_parse(
             pluginmanager=pluginmanager, args=args
         )

src/_pytest/deprecated.py

@@ -9,9 +9,14 @@ from __future__ import absolute_import, division, print_function
 
 from _pytest.warning_types import RemovedInPytest4Warning
 
-MAIN_STR_ARGS = "passing a string to pytest.main() is deprecated, " "pass a list of arguments instead."
+MAIN_STR_ARGS = RemovedInPytest4Warning(
+    "passing a string to pytest.main() is deprecated, "
+    "pass a list of arguments instead."
+)
 
-YIELD_TESTS = "yield tests are deprecated, and scheduled to be removed in pytest 4.0"
+YIELD_TESTS = RemovedInPytest4Warning(
+    "yield tests are deprecated, and scheduled to be removed in pytest 4.0"
+)
 
 FUNCARG_PREFIX = (
     '{name}: declaring fixtures using "pytest_funcarg__" prefix is deprecated '
@@ -48,7 +53,11 @@ MARK_PARAMETERSET_UNPACKING = RemovedInPytest4Warning(
     "For more details, see: https://docs.pytest.org/en/latest/parametrize.html"
 )
 
-RECORD_XML_PROPERTY = (
+NODE_WARN = RemovedInPytest4Warning(
+    "Node.warn has been deprecated, use Node.std_warn instead"
+)
+
+RECORD_XML_PROPERTY = RemovedInPytest4Warning(
     'Fixture renamed from "record_xml_property" to "record_property" as user '
     "properties are now available to all reporters.\n"
     '"record_xml_property" is now deprecated.'
@@ -58,7 +67,7 @@ COLLECTOR_MAKEITEM = RemovedInPytest4Warning(
     "pycollector makeitem was removed " "as it is an accidentially leaked internal api"
 )
 
-METAFUNC_ADD_CALL = (
+METAFUNC_ADD_CALL = RemovedInPytest4Warning(
     "Metafunc.addcall is deprecated and scheduled to be removed in pytest 4.0.\n"
     "Please use Metafunc.parametrize instead."
 )

src/_pytest/fixtures.py

@@ -1257,6 +1257,8 @@ class FixtureManager(object):
         items[:] = reorder_items(items)
 
     def parsefactories(self, node_or_obj, nodeid=NOTSET, unittest=False):
+        from _pytest import deprecated
+
         if nodeid is not NOTSET:
             holderobj = node_or_obj
         else:
@@ -1279,7 +1281,6 @@ class FixtureManager(object):
                 if not callable(obj):
                     continue
                 marker = defaultfuncargprefixmarker
-                from _pytest import deprecated
 
                 filename, lineno = getfslineno(obj)
                 warnings.warn_explicit(

src/_pytest/junitxml.py

@@ -262,7 +262,7 @@ def record_xml_property(record_property, request):
     """(Deprecated) use record_property."""
     from _pytest import deprecated
 
-    request.node.std_warn(deprecated.RECORD_XML_PROPERTY, DeprecationWarning)
+    request.node.std_warn(deprecated.RECORD_XML_PROPERTY)
 
     return record_property
 
@@ -276,8 +276,7 @@ def record_xml_attribute(request):
     from _pytest.warning_types import PytestWarning
 
     request.node.std_warn(
-        message="record_xml_attribute is an experimental feature",
+        PytestWarning("record_xml_attribute is an experimental feature")
-        category=PytestWarning,
     )
     xml = getattr(request.config, "_xml", None)
     if xml is not None:

src/_pytest/mark/structures.py

@@ -65,7 +65,7 @@ class ParameterSet(namedtuple("ParameterSet", "values, marks, id")):
         return cls(values, marks, id_)
 
     @classmethod
-    def extract_from(cls, parameterset, legacy_force_tuple=False, item=None):
+    def extract_from(cls, parameterset, belonging_definition, legacy_force_tuple=False):
         """
         :param parameterset:
             a legacy style parameterset that may or may not be a tuple,
@@ -75,7 +75,7 @@ class ParameterSet(namedtuple("ParameterSet", "values, marks, id")):
             enforce tuple wrapping so single argument tuple values
             don't get decomposed and break tests
 
-        :param item: the item that we will be extracting the parameters from.
+        :param belonging_definition: the item that we will be extracting the parameters from.
         """
 
         if isinstance(parameterset, cls):
@@ -94,8 +94,8 @@ class ParameterSet(namedtuple("ParameterSet", "values, marks, id")):
         if legacy_force_tuple:
             argval = (argval,)
 
-        if newmarks and item is not None:
+        if newmarks and belonging_definition is not None:
-            item.std_warn(MARK_PARAMETERSET_UNPACKING)
+            belonging_definition.std_warn(MARK_PARAMETERSET_UNPACKING)
 
         return cls(argval, marks=newmarks, id=None)
 
@@ -108,7 +108,9 @@ class ParameterSet(namedtuple("ParameterSet", "values, marks, id")):
             force_tuple = False
         parameters = [
             ParameterSet.extract_from(
-                x, legacy_force_tuple=force_tuple, item=function_definition
+                x,
+                legacy_force_tuple=force_tuple,
+                belonging_definition=function_definition,
             )
             for x in argvalues
         ]

src/_pytest/nodes.py

@@ -144,12 +144,9 @@ class Node(object):
 
         Generate a warning with the given code and message for this item.
         """
-        from _pytest.warning_types import RemovedInPytest4Warning
+        from _pytest.deprecated import NODE_WARN
 
-        self.std_warn(
+        self.std_warn(NODE_WARN)
-            "Node.warn has been deprecated, use Node.std_warn instead",
-            RemovedInPytest4Warning,
-        )
 
         assert isinstance(code, str)
         fslocation = get_fslocation_from_item(self)
@@ -159,22 +156,27 @@ class Node(object):
             )
         )
 
-    def std_warn(self, message, category=None):
+    def std_warn(self, warning):
         """Issue a warning for this item.
 
         Warnings will be displayed after the test session, unless explicitly suppressed
 
-        :param Union[str,Warning] message: text message of the warning or ``Warning`` instance.
+        :param Warning warning: the warning instance to issue. Must be a subclass of PytestWarning.
-        :param Type[Warning] category: warning category.
+
+        :raise ValueError: if ``warning`` instance is not a subclass of PytestWarning.
         """
         from _pytest.warning_types import PytestWarning
 
-        if category is None:
+        if not isinstance(warning, PytestWarning):
-            assert isinstance(message, PytestWarning)
+            raise ValueError(
+                "warning must be an instance of PytestWarning or subclass, got {!r}".format(
+                    warning
+                )
+            )
         path, lineno = get_fslocation_from_item(self)
         warnings.warn_explicit(
-            message,
+            six.text_type(warning),
-            category,
+            type(warning),
             filename=str(path),
             lineno=lineno + 1 if lineno is not None else None,
         )

src/_pytest/pytester.py

@@ -126,7 +126,7 @@ class LsofFdLeakChecker(object):
             error.append(error[0])
             error.append("*** function %s:%s: %s " % item.location)
             error.append("See issue #2366")
-            item.std_warn("", "\n".join(error), pytest.PytestWarning)
+            item.std_warn(pytest.PytestWarning("\n".join(error)))
 
 
 # XXX copied from execnet's conftest.py - needs to be merged
@@ -643,11 +643,9 @@ class Testdir(object):
 
     def copy_example(self, name=None):
         import warnings
+        from _pytest.warning_types import PYTESTER_COPY_EXAMPLE
 
-        warnings.warn(
+        warnings.warn(PYTESTER_COPY_EXAMPLE, stacklevel=2)
-            pytest.PytestExperimentalApiWarning.simple("testdir.copy_example"),
-            stacklevel=2,
-        )
         example_dir = self.request.config.getini("pytester_example_dir")
         if example_dir is None:
             raise ValueError("pytester_example_dir is unset, can't copy examples")

src/_pytest/python.py

@@ -660,9 +660,10 @@ class Class(PyCollector):
             return []
         if hasinit(self.obj):
             self.std_warn(
-                "cannot collect test class %r because it has a "
+                PytestWarning(
-                "__init__ constructor" % self.obj.__name__,
+                    "cannot collect test class %r because it has a "
-                PytestWarning,
+                    "__init__ constructor" % self.obj.__name__
+                )
             )
             return []
         elif hasnew(self.obj):
@@ -798,7 +799,7 @@ class Generator(FunctionMixin, PyCollector):
                 )
             seen[name] = True
             values.append(self.Function(name, self, args=args, callobj=call))
-        self.std_warn(deprecated.YIELD_TESTS, RemovedInPytest4Warning)
+        self.std_warn(deprecated.YIELD_TESTS)
         return values
 
     def getcallargs(self, obj):
@@ -1105,9 +1106,7 @@ class Metafunc(fixtures.FuncargnamesCompatAttr):
             invocation through the ``request.param`` attribute.
         """
         if self.config:
-            self.definition.std_warn(
+            self.definition.std_warn(deprecated.METAFUNC_ADD_CALL)
-                deprecated.METAFUNC_ADD_CALL, RemovedInPytest4Warning
-            )
 
         assert funcargs is None or isinstance(funcargs, dict)
         if funcargs is not None:
@@ -1158,22 +1157,20 @@ def _find_parametrized_scope(argnames, arg2fixturedefs, indirect):
     return "function"
 
 
-def _idval(val, argname, idx, idfn, config=None, item=None):
+def _idval(val, argname, idx, idfn, item, config=None):
     if idfn:
         s = None
         try:
             s = idfn(val)
         except Exception as e:
             # See issue https://github.com/pytest-dev/pytest/issues/2169
-            if item is not None:
+            msg = (
-                # should really be None only when unit-testing this function!
+                "While trying to determine id of parameter {} at position "
-                msg = (
+                "{} the following exception was raised:\n".format(argname, idx)
-                    "While trying to determine id of parameter {} at position "
+            )
-                    "{} the following exception was raised:\n".format(argname, idx)
+            msg += "  {}: {}\n".format(type(e).__name__, e)
-                )
+            msg += "This warning will be an error error in pytest-4.0."
-                msg += "  {}: {}\n".format(type(e).__name__, e)
+            item.std_warn(RemovedInPytest4Warning(msg))
-                msg += "This warning will be an error error in pytest-4.0."
-                item.std_warn(msg, RemovedInPytest4Warning)
         if s:
             return ascii_escaped(s)
 
@@ -1202,7 +1199,7 @@ def _idvalset(idx, parameterset, argnames, idfn, ids, config=None, item=None):
         return parameterset.id
     if ids is None or (idx >= len(ids) or ids[idx] is None):
         this_id = [
-            _idval(val, argname, idx, idfn, config, item)
+            _idval(val, argname, idx, idfn, item=item, config=config)
             for val, argname in zip(parameterset.values, argnames)
         ]
         return "-".join(this_id)

src/_pytest/warning_types.py

@@ -37,3 +37,6 @@ class PytestExperimentalApiWarning(PytestWarning, FutureWarning):
                 apiname=apiname
             )
         )
+
+
+PYTESTER_COPY_EXAMPLE = PytestExperimentalApiWarning.simple("testdir.copy_example")

src/_pytest/warnings.py

@@ -129,20 +129,20 @@ def warning_record_to_str(warning_message):
     return msg
 
 
-@pytest.hookimpl(hookwrapper=True)
+@pytest.hookimpl(hookwrapper=True, tryfirst=True)
 def pytest_runtest_protocol(item):
     with catch_warnings_for_item(config=item.config, ihook=item.ihook, item=item):
         yield
 
 
-@pytest.hookimpl(hookwrapper=True)
+@pytest.hookimpl(hookwrapper=True, tryfirst=True)
 def pytest_collection(session):
     config = session.config
     with catch_warnings_for_item(config=config, ihook=config.hook, item=None):
         yield
 
 
-@pytest.hookimpl(hookwrapper=True)
+@pytest.hookimpl(hookwrapper=True, tryfirst=True)
 def pytest_terminal_summary(terminalreporter):
     config = terminalreporter.config
     with catch_warnings_for_item(config=config, ihook=config.hook, item=None):

testing/acceptance_test.py

@@ -526,7 +526,7 @@ class TestInvocationVariants(object):
         assert pytest.main == py.test.cmdline.main
 
     def test_invoke_with_string(self, capsys):
-        retcode = pytest.main(["-h"])
+        retcode = pytest.main("-h")
         assert not retcode
         out, err = capsys.readouterr()
         assert "--help" in out

testing/deprecated_test.py

@@ -289,6 +289,7 @@ def test_call_fixture_function_deprecated():
 
 def test_pycollector_makeitem_is_deprecated():
     from _pytest.python import PyCollector
+    from _pytest.warning_types import RemovedInPytest4Warning
 
     class PyCollectorMock(PyCollector):
         """evil hack"""
@@ -301,6 +302,6 @@ def test_pycollector_makeitem_is_deprecated():
             self.called = True
 
     collector = PyCollectorMock()
-    with pytest.deprecated_call():
+    with pytest.warns(RemovedInPytest4Warning):
         collector.makeitem("foo", "bar")
     assert collector.called

testing/python/metafunc.py

@@ -217,7 +217,7 @@ class TestMetafunc(object):
     def test_idval_hypothesis(self, value):
         from _pytest.python import _idval
 
-        escaped = _idval(value, "a", 6, None)
+        escaped = _idval(value, "a", 6, None, item=None)
         assert isinstance(escaped, str)
         if PY3:
             escaped.encode("ascii")
@@ -244,7 +244,7 @@ class TestMetafunc(object):
             ),
         ]
         for val, expected in values:
-            assert _idval(val, "a", 6, None) == expected
+            assert _idval(val, "a", 6, None, item=None) == expected
 
     def test_bytes_idval(self):
         """unittest for the expected behavior to obtain ids for parametrized
@@ -262,7 +262,7 @@ class TestMetafunc(object):
             (u"αρά".encode("utf-8"), "\\xce\\xb1\\xcf\\x81\\xce\\xac"),
         ]
         for val, expected in values:
-            assert _idval(val, "a", 6, None) == expected
+            assert _idval(val, "a", 6, idfn=None, item=None, config=None) == expected
 
     def test_class_or_function_idval(self):
         """unittest for the expected behavior to obtain ids for parametrized
@@ -278,7 +278,7 @@ class TestMetafunc(object):
 
         values = [(TestClass, "TestClass"), (test_function, "test_function")]
         for val, expected in values:
-            assert _idval(val, "a", 6, None) == expected
+            assert _idval(val, "a", 6, None, item=None) == expected
 
     @pytest.mark.issue250
     def test_idmaker_autoname(self):

testing/test_mark.py

@@ -1041,7 +1041,11 @@ class TestKeywordSelection(object):
 )
 @pytest.mark.filterwarnings("ignore")
 def test_parameterset_extractfrom(argval, expected):
-    extracted = ParameterSet.extract_from(argval)
+    class DummyItem:
+        def std_warn(self, warning):
+            pass
+
+    extracted = ParameterSet.extract_from(argval, belonging_definition=DummyItem())
     assert extracted == expected
 
 

testing/test_nodes.py

@@ -19,3 +19,14 @@ from _pytest import nodes
 def test_ischildnode(baseid, nodeid, expected):
     result = nodes.ischildnode(baseid, nodeid)
     assert result is expected
+
+
+def test_std_warn_not_pytestwarning(testdir):
+    items = testdir.getitems(
+        """
+        def test():
+            pass
+    """
+    )
+    with pytest.raises(ValueError, match=".*instance of PytestWarning.*"):
+        items[0].std_warn(UserWarning("some warning"))