SONARPY-3563 Fix S100 false positives on unittest/Django test lifecycle methods (#988)

Co-authored-by: Vibe Bot <vibe-bot@sonarsource.com>
GitOrigin-RevId: 011d31e86ca30961048c71bad5676aaf336c1c1b

Author: 2 people

python-checks/src/main/java/org/sonar/python/checks/MethodNameCheck.java

@@ -16,6 +16,7 @@
  */
 package org.sonar.python.checks;
 
+import java.util.Set;
 import org.sonar.check.Rule;
 import org.sonar.plugins.python.api.tree.FunctionDef;
 
@@ -26,13 +27,17 @@
 public class MethodNameCheck extends AbstractFunctionNameCheck {
   public static final String CHECK_KEY = "S100";
 
+  private static final Set<String> WHITELIST = Set.of("setUp", "tearDown", "setUpClass", "tearDownClass", "setUpTestData");
+
   @Override
   public String typeName() {
     return "method";
   }
 
   @Override
   public boolean shouldCheckFunctionDeclaration(FunctionDef pyFunctionDefTree) {
-    return pyFunctionDefTree.isMethodDefinition() && !classHasInheritance(getParentClassDef(pyFunctionDefTree));
+    return pyFunctionDefTree.isMethodDefinition()
+      && !classHasInheritance(getParentClassDef(pyFunctionDefTree))
+      && !WHITELIST.contains(pyFunctionDefTree.name().name());
   }
 }

python-checks/src/main/java/org/sonar/python/checks/utils/CheckUtils.java

@@ -105,7 +105,10 @@ public static ClassDef getParentClassDef(Tree tree) {
     return null;
   }
 
-  public static boolean classHasInheritance(ClassDef classDef) {
+  public static boolean classHasInheritance(@Nullable ClassDef classDef) {
+    if (classDef == null) {
+      return false;
+    }
     ArgList argList = classDef.args();
     if (argList == null) {
       return false;

python-checks/src/test/resources/checks/methodName.py

@@ -56,3 +56,41 @@ def y(self):  # OK
 
   def _v(self):
     ...
+
+class TestMixin:
+    @classmethod
+    def setUpTestData(cls):
+        pass
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    @classmethod
+    def setUpClass(cls):
+        pass
+
+    @classmethod
+    def tearDownClass(cls):
+        pass
+
+class TestMixinWithObjectBase(object):
+    def setUp(self):  # OK, whitelisted lifecycle method even in class inheriting from object
+        pass
+
+    def tearDown(self):  # OK, whitelisted lifecycle method
+        pass
+
+    @classmethod
+    def setUpClass(cls):  # OK, whitelisted lifecycle method
+        pass
+
+    @classmethod
+    def tearDownClass(cls):  # OK, whitelisted lifecycle method
+        pass
+
+    @classmethod
+    def setUpTestData(cls):  # OK, whitelisted lifecycle method
+        pass