Add new INI config key 'required_plugins' that defines a list of plugins that must be present for a run of pytest

changelog/7305.feature.rst

@@ -0,0 +1 @@
+New ``required_plugins`` configuration option allows the user to specify a list of plugins required for pytest to run. An error is raised if any required plugins are not found when running pytest.

doc/en/reference.rst

@@ -1561,6 +1561,17 @@ passed multiple times. The expected format is ``name=value``. For example::
    See :ref:`change naming conventions` for more detailed examples.
 
 
+.. confval:: required_plugins
+
+   A space separated list of plugins that must be present for pytest to run.
+   If any one of the plugins is not found, emit an error.
+
+   .. code-block:: ini
+
+       [pytest]
+       required_plugins = pytest-html pytest-xdist
+
+
 .. confval:: testpaths
 
 

src/_pytest/config/__init__.py

@@ -952,6 +952,12 @@ def _initini(self, args: Sequence[str]) -> None:
         self._parser.extra_info["inifile"] = self.inifile
         self._parser.addini("addopts", "extra command line options", "args")
         self._parser.addini("minversion", "minimally required pytest version")
+        self._parser.addini(
+            "required_plugins",
+            "plugins that must be present for pytest to run",
+            type="args",
+            default=[],
+        )
         self._override_ini = ns.override_ini or ()
 
     def _consider_importhook(self, args: Sequence[str]) -> None:
@@ -1035,7 +1041,8 @@ def _preparse(self, args: List[str], addopts: bool = True) -> None:
         self.known_args_namespace = ns = self._parser.parse_known_args(
             args, namespace=copy.copy(self.option)
         )
-        self._validatekeys()
+        self._validate_plugins()
+        self._validate_keys()
         if self.known_args_namespace.confcutdir is None and self.inifile:
             confcutdir = py.path.local(self.inifile).dirname
             self.known_args_namespace.confcutdir = confcutdir
@@ -1078,12 +1085,33 @@ def _checkversion(self):
                     )
                 )
 
-    def _validatekeys(self):
+    def _validate_keys(self) -> None:
         for key in sorted(self._get_unknown_ini_keys()):
-            message = "Unknown config ini key: {}\n".format(key)
-            if self.known_args_namespace.strict_config:
-                fail(message, pytrace=False)
-            sys.stderr.write("WARNING: {}".format(message))
+            self._warn_or_fail_if_strict("Unknown config ini key: {}\n".format(key))
+
+    def _validate_plugins(self) -> None:
+        required_plugins = sorted(self.getini("required_plugins"))
+        if not required_plugins:
+            return
+
+        plugin_info = self.pluginmanager.list_plugin_distinfo()
+        plugin_dist_names = [dist.project_name for _, dist in plugin_info]
+
+        missing_plugins = []
+        for plugin in required_plugins:
+            if plugin not in plugin_dist_names:
+                missing_plugins.append(plugin)
+
+        if missing_plugins:
+            fail(
+                "Missing required plugins: {}".format(", ".join(missing_plugins)),
+                pytrace=False,
+            )
+
+    def _warn_or_fail_if_strict(self, message: str) -> None:
+        if self.known_args_namespace.strict_config:
+            fail(message, pytrace=False)
+        sys.stderr.write("WARNING: {}".format(message))
 
     def _get_unknown_ini_keys(self) -> List[str]:
         parser_inicfg = self._parser._inidict

src/_pytest/main.py

@@ -78,7 +78,7 @@ def pytest_addoption(parser: Parser) -> None:
     group._addoption(
         "--strict-config",
         action="store_true",
-        help="invalid ini keys for the `pytest` section of the configuration file raise errors.",
+        help="any warnings encountered while parsing the `pytest` section of the configuration file raise errors.",
     )
     group._addoption(
         "--strict-markers",

testing/test_config.py

@@ -212,6 +212,60 @@ def test_invalid_ini_keys(
             with pytest.raises(pytest.fail.Exception, match=exception_text):
                 testdir.runpytest("--strict-config")
 
+    @pytest.mark.parametrize(
+        "ini_file_text, exception_text",
+        [
+            (
+                """
+          [pytest]
+          required_plugins = fakePlugin1 fakePlugin2
+          """,
+                "Missing required plugins: fakePlugin1, fakePlugin2",
+            ),
+            (
+                """
+          [pytest]
+          required_plugins = a pytest-xdist z
+          """,
+                "Missing required plugins: a, z",
+            ),
+            (
+                """
+          [pytest]
+          required_plugins = a q j b c z
+          """,
+                "Missing required plugins: a, b, c, j, q, z",
+            ),
+            (
+                """
+          [some_other_header]
+          required_plugins = wont be triggered
+          [pytest]
+          minversion = 5.0.0
+          """,
+                "",
+            ),
+            (
+                """
+          [pytest]
+          minversion = 5.0.0
+          """,
+                "",
+            ),
+        ],
+    )
+    def test_missing_required_plugins(self, testdir, ini_file_text, exception_text):
+        pytest.importorskip("xdist")
+
+        testdir.tmpdir.join("pytest.ini").write(textwrap.dedent(ini_file_text))
+        testdir.monkeypatch.delenv("PYTEST_DISABLE_PLUGIN_AUTOLOAD")
+
+        if exception_text:
+            with pytest.raises(pytest.fail.Exception, match=exception_text):
+                testdir.parseconfig()
+        else:
+            testdir.parseconfig()
+
 
 class TestConfigCmdlineParsing:
     def test_parsing_again_fails(self, testdir):
@@ -610,6 +664,7 @@ class PseudoPlugin:
 
     class Dist:
         files = ()
+        metadata = {"name": "foo"}
         entry_points = (EntryPoint(),)
 
     def my_dists():
@@ -640,6 +695,7 @@ def load(self):
     class Distribution:
         version = "1.0"
         files = ("foo.txt",)
+        metadata = {"name": "foo"}
         entry_points = (DummyEntryPoint(),)
 
     def distributions():
@@ -664,6 +720,7 @@ def load(self):
     class Distribution:
         version = "1.0"
         files = None
+        metadata = {"name": "foo"}
         entry_points = (DummyEntryPoint(),)
 
     def distributions():
@@ -689,6 +746,7 @@ def load(self):
     class Distribution:
         version = "1.0"
         files = ("foo.txt",)
+        metadata = {"name": "foo"}
         entry_points = (DummyEntryPoint(),)
 
     def distributions():
@@ -720,6 +778,7 @@ def load(self):
             return sys.modules[self.name]
 
     class Distribution:
+        metadata = {"name": "foo"}
         entry_points = (DummyEntryPoint(),)
         files = ()