Start the laywork to capture standard warnings

src/_pytest/deprecated.py

@@ -7,10 +7,7 @@ be removed when the time comes.
 """
 from __future__ import absolute_import, division, print_function
 
-
-class RemovedInPytest4Warning(DeprecationWarning):
-    """warning class for features removed in pytest 4.0"""
-
+from _pytest.warning_types import RemovedInPytest4Warning
 
 MAIN_STR_ARGS = "passing a string to pytest.main() is deprecated, " "pass a list of arguments instead."
 

src/_pytest/nodes.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import, division, print_function
 import os
+import warnings
 
 import six
 import py
@@ -7,6 +8,7 @@ import attr
 
 import _pytest
 import _pytest._code
+from _pytest.compat import getfslineno
 
 from _pytest.mark.structures import NodeKeywords, MarkInfo
 
@@ -145,6 +147,14 @@ class Node(object):
             )
         )
 
+    def std_warn(self, message, category=None):
+        from _pytest.warning_types import PytestWarning
+
+        if category is None:
+            assert isinstance(message, PytestWarning)
+        path, lineno = get_fslocation_from_item(self)
+        warnings.warn_explicit(message, category, filename=str(path), lineno=lineno)
+
     # methods for ordering nodes
     @property
     def nodeid(self):
@@ -314,10 +324,13 @@ def get_fslocation_from_item(item):
     * "fslocation": a pair (path, lineno)
     * "fspath": just a path
     """
-    fslocation = getattr(item, "location", None)
-    if fslocation is None:
-        fslocation = getattr(item, "fspath", None)
-    return fslocation
+    result = getattr(item, "location", None)
+    if result is not None:
+        return result
+    obj = getattr(item, "obj", None)
+    if obj is not None:
+        return getfslineno(obj)
+    return getattr(item, "fspath", None), None
 
 
 class Collector(Node):

src/_pytest/python.py

@@ -44,7 +44,7 @@ from _pytest.mark.structures import (
     get_unpacked_marks,
     normalize_mark_list,
 )
-
+from _pytest.warning_types import PytestUsageWarning
 
 # relative paths that we use to filter traceback entries from appearing to the user;
 # see filter_traceback
@@ -656,17 +656,23 @@ class Class(PyCollector):
         if not safe_getattr(self.obj, "__test__", True):
             return []
         if hasinit(self.obj):
-            self.warn(
-                "C1",
+            # self.warn(
+            #     "C1",
+            #     "cannot collect test class %r because it has a "
+            #     "__init__ constructor" % self.obj.__name__,
+            # )
+            self.std_warn(
                 "cannot collect test class %r because it has a "
                 "__init__ constructor" % self.obj.__name__,
+                PytestUsageWarning,
             )
             return []
         elif hasnew(self.obj):
-            self.warn(
-                "C1",
-                "cannot collect test class %r because it has a "
-                "__new__ constructor" % self.obj.__name__,
+            self.std_warn(
+                PytestUsageWarning(
+                    "cannot collect test class %r because it has a "
+                    "__new__ constructor" % self.obj.__name__
+                )
             )
             return []
         return [self._getcustomclass("Instance")(name="()", parent=self)]

src/_pytest/terminal.py

@@ -331,12 +331,11 @@ class TerminalReporter(object):
         warnings.append(warning)
 
     def pytest_warning_captured(self, warning_message, item):
-        from _pytest.nodes import get_fslocation_from_item
+        # from _pytest.nodes import get_fslocation_from_item
         from _pytest.warnings import warning_record_to_str
 
         warnings = self.stats.setdefault("warnings", [])
-
-        fslocation = get_fslocation_from_item(item)
+        fslocation = warning_message.filename, warning_message.lineno
         message = warning_record_to_str(warning_message)
 
         nodeid = item.nodeid if item is not None else ""
@@ -713,7 +712,7 @@ class TerminalReporter(object):
                 for w in warning_records:
                     lines = w.message.splitlines()
                     indented = "\n".join("  " + x for x in lines)
-                    self._tw.line(indented)
+                    self._tw.line(indented.rstrip())
                 self._tw.line()
             self._tw.line("-- Docs: https://docs.pytest.org/en/latest/warnings.html")
 

src/_pytest/warning_types.py

@@ -0,0 +1,10 @@
+class PytestWarning(UserWarning):
+    """Base class for all warnings emitted by pytest"""
+
+
+class PytestUsageWarning(PytestWarning):
+    """Warnings related to pytest usage: either command line or testing code."""
+
+
+class RemovedInPytest4Warning(PytestWarning):
+    """warning class for features that will be removed in pytest 4.0"""

testing/test_mark.py

@@ -16,7 +16,7 @@ from _pytest.mark import (
 from _pytest.nodes import Node
 
 ignore_markinfo = pytest.mark.filterwarnings(
-    "ignore:MarkInfo objects:_pytest.deprecated.RemovedInPytest4Warning"
+    "ignore:MarkInfo objects:_pytest.warning_types.RemovedInPytest4Warning"
 )