warn specific classes

Author: graingert

src/pytest_cov/compat.py

@@ -1,12 +1,15 @@
+import warnings
+
+import pytest
+
 try:
     from StringIO import StringIO
 except ImportError:
     from io import StringIO
 
-import pytest
-
 StringIO  # pyflakes, this is for re-export
 
+PYTEST_VERSION = tuple(int(v) for v in pytest.__version__.split('.')[:3])
 
 if hasattr(pytest, 'hookimpl'):
     hookwrapper = pytest.hookimpl(hookwrapper=True)
@@ -44,6 +47,21 @@ def fn(obj, *args):
     return fn
 
 
+if PYTEST_VERSION >= (3, 8):
+    def warn(config, message, category, stacklevel=1):
+        return warnings.warn(
+            message=message,
+            category=category,
+            stacklevel=stacklevel+1,
+        )
+else:
+    def warn(config, message, category, stacklevel=1):
+        return config.warn(
+            code=category.code,
+            message=message,
+        )
+
+
 worker = 'slave'  # for compatability with pytest-xdist<=1.22.0
 workerid = worker + 'id'
 workerinput = _attrgetter(worker + 'input')

src/pytest_cov/plugin.py

@@ -1,7 +1,6 @@
 """Coverage plugin for pytest."""
 import argparse
 import os
-import warnings
 
 import coverage
 import pytest
@@ -11,13 +10,28 @@
 from . import embed
 from . import engine
 
-PYTEST_VERSION = tuple(map(int, pytest.__version__.split('.')[:3]))
-
 
 class CoverageError(Exception):
     """Indicates that our coverage is too low"""
 
 
+class PytestCovWarning(pytest.PytestWarning):
+    """
+    The base for all pytest-cov warnings, never raised directly
+    """
+    code = "COV-0"
+
+
+class CovDisabledWarning(PytestCovWarning):
+    """Indicates that Coverage was manually disabled"""
+    code = "COV-1"
+
+
+class CovReportWarning(PytestCovWarning):
+    """Indicates that we failed to generate a report"""
+    code = "COV-2"
+
+
 def validate_report(arg):
     file_choices = ['annotate', 'html', 'xml']
     term_choices = ['term', 'term-missing']
@@ -262,10 +276,11 @@ def pytest_runtestloop(self, session):
                 message = 'Failed to generate report: %s\n' % exc
                 session.config.pluginmanager.getplugin("terminalreporter").write(
                     'WARNING: %s\n' % message, red=True, bold=True)
-                if PYTEST_VERSION >= (3, 8):
-                    warnings.warn(pytest.PytestWarning(message))
-                else:
-                    session.config.warn(code='COV-2', message=message)
+                compat.warn(
+                    config=session.config,
+                    message=message,
+                    category=CovReportWarning,
+                )
                 self.cov_total = 0
             assert self.cov_total is not None, 'Test coverage should never be `None`'
             if self._failed_cov_total():
@@ -276,10 +291,11 @@ def pytest_terminal_summary(self, terminalreporter):
         if self._disabled:
             message = 'Coverage disabled via --no-cov switch!'
             terminalreporter.write('WARNING: %s\n' % message, red=True, bold=True)
-            if PYTEST_VERSION >= (3, 8):
-                warnings.warn(pytest.PytestWarning(message))
-            else:
-                terminalreporter.config.warn(code='COV-1', message=message)
+            compat.warn(
+                config=terminalreporter.config,
+                message=message,
+                category=CovDisabledWarning,
+            )
             return
         if self.cov_controller is None:
             return