Java: remove redundant 'non-static' wording and update qhelp

Author: Jami Cogswell

java/ql/src/Likely Bugs/Frameworks/JUnit/JUnit5NonStaticInnerClassMissingNestedAnnotation.md

@@ -1,16 +1,10 @@
-# J-T-004: Non-static inner class defined in a JUnit 5 is missing a `@Nested` annotation
-
-A non-static inner class defined in a JUnit 5 test missing a `@Nested` annotation will be excluded from execution and it may indicate a misunderstanding from the programmer.
-
 ## Overview
 
-JUnit tests are grouped in a class, and starting from JUnit 5 users can group the test classes in a bigger class so they can share the local environment of the enclosing class. While this helps to organize the unit tests and foster code reuse, if the inner class is not annotated with `@Nested`, the unit tests in it will fail to execute during builds.
-
-Note that static classes, whether static or not, behave as independent sets of unit tests. Thus, inner static classes do not share the information provided by the outer class with other inner classes. Thus, this rule only applies to non-static JUnit 5 inner classes.
+JUnit tests are grouped in a class, and starting from JUnit 5 users can group the test classes in a bigger class so they can share the local environment of the enclosing class. While this helps to organize the unit tests and foster code reuse, if an inner test class is not annotated with `@Nested`, the unit tests in it will fail to execute during builds.
 
 ## Recommendation
 
-If you want the tests defined in an inner class to be recognized by the build plugin and be executed, annotate with `@Nested`, imported from `org.junit.jupiter.api`.
+If you want the tests defined in an inner class to be recognized by the build plugin and be executed, annotate the class with `@Nested`, imported from `org.junit.jupiter.api`.
 
 ## Example
 
@@ -19,53 +13,33 @@ import org.junit.jupiter.api.Nested;
 import static org.junit.Assert.assertEquals;
 
 public class IntegerOperationTest {
-  private int i;                // Shared variable among the inner classes.
+  private int i;  // Shared variable among the inner classes.
 
   @BeforeEach
   public void initTest() { i = 0; }
 
   @Nested
-  public class AdditionTest {   // COMPLIANT: Inner test class annotated with `@Nested`.
+  public class AdditionTest {  // COMPLIANT: Inner test class annotated with `@Nested`.
     @Test
-    public void addTest1() {    // Test of an inner class, implying `AdditionTest` is a test class.
-      assertEquals(1, i+1);
+    public void addTest1() {
+      assertEquals(1, i + 1);
     }
   }
 
-  public class SubtractionTest { // NON_COMPLIANT: Inner test class missing `@Nested`.
+  public class SubtractionTest {  // NON_COMPLIANT: Inner test class missing `@Nested`.
     @Test
-    public void addTest1() {     // Test of an inner class, implying `SubtractionTest` is a test class.
-      assertEquals(-1, i-1);
+    public void addTest1() {
+      assertEquals(-1, i - 1);
     }
   }
-
-  static public class MultiplicationTest {  // COMPLIANT: static test class should not be annotated as `@Nested`.
-    ...
-  }
 }
 ```
 
 ## Implementation Notes
 
-The `@Nested` annotation does not apply to inner static classes, since the meaning of the annotation is to mark a class as "a *non-static* inner class containing `@Test` methods to be picked up by a build system". It also does not apply to inner abstract classes since there is no use case for an `@Nested` annotation on an abstract class. Therefore, this rule does not aim to target static or abstract inner test classes with a `@Nested` annotation, nor does it try to enforce such correct usage of `@Nested`. Therefore, any code that resembles the below is not non-compliant to this rule.
-
-``` java
-@Nested
-public static class TestStatic { // COMPLIANT: Although invalid, this matter is out of the scope
-  @Test
-  public void test() {
-  }
-}
-
-@Nested
-public abstract class TestAbstract { // COMPLIANT: Although invalid, this matter is out of the scope
-  @Test
-  public void test() {
-  }
-}
-```
+This rule is focused on missing `@Nested` annotations on non-static nested (inner) test classes. Static nested test classes and abstract nested test classes should not be annotated with `@Nested`. As a result, the absence of a `@Nested` annotation on such classes is compliant. Identifying incorrect application of a `@Nested` annotation to static and abstract classes is out of scope for this rule.
 
 ## References
 
-- JUnit: [Documentation on `@Nested`](https://junit.org/junit5/docs/current/api/org.junit.jupiter.api/org/junit/jupiter/api/Nested.html).
-- Baeldung: [JUnit 5 @Nested Test Classes](https://www.baeldung.com/junit-5-nested-test-classes).
+- JUnit 5 API Documentation: [Annotation Interface Nested](https://junit.org/junit5/docs/current/api/org.junit.jupiter.api/org/junit/jupiter/api/Nested.html).
+- JUnit 5 User Guide: [Nested Tests](https://junit.org/junit5/docs/current/user-guide/#writing-tests-nested).

java/ql/src/Likely Bugs/Frameworks/JUnit/JUnit5NonStaticInnerClassMissingNestedAnnotation.ql

@@ -1,15 +1,16 @@
 /**
- * @id java/junit5-non-static-inner-class-missing-nested-annotation
- * @name Non-static inner class defined in a JUnit 5 test is missing a `@Nested` annotation
- * @description A non-static inner class defined in a JUnit 5 test missing a `@Nested` annotation
- *              will be excluded from execution and it may indicate a misunderstanding from the
+ * @id java/junit5-missing-nested-annotation
+ * @name Missing `@Nested` annotation on JUnit 5 inner test class
+ * @description A JUnit 5 inner test class that is missing a `@Nested` annotation will be
+ *              excluded from execution and it may indicate a misunderstanding from the
  *              programmer.
  * @kind problem
  * @precision very-high
  * @problem.severity warning
  * @tags quality
  *       maintainability
  *       correctness
+ *       prior-id:java/junit5-non-static-inner-class-missing-nested-annotation
  */
 
 import java
@@ -21,4 +22,4 @@ where
   not testClass.hasAnnotation("org.junit.jupiter.api", "Nested") and
   // An abstract class should not have a `@Nested` annotation
   not testClass.isAbstract()
-select testClass, "This JUnit5 inner test class lacks a '@Nested' annotation."
+select testClass, "This JUnit 5 inner test class lacks a '@Nested' annotation."

java/ql/src/change-notes/2025-03-21-junit-missing-nested-annotation.md

@@ -1,4 +1,4 @@
 ---
 category: newQuery
 ---
-* Added a new quality query, `java/junit5-non-static-inner-class-missing-nested-annotation`, to detect missing `@Nested` annotations on non-static, inner JUnit 5 test classes.
+* Added a new quality query, `java/junit5-missing-nested-annotation`, to detect missing `@Nested` annotations on JUnit 5 inner test classes.

java/ql/test/query-tests/Likely Bugs/Frameworks/JUnit/AnnotationTest.java

@@ -30,7 +30,7 @@ public void h() {
     }
   }
 
-  public static class Test5 { // COMPLIANT: Static inner test classes don't need `@Nested`
+  public static class Test5 { // COMPLIANT: Static nested test classes don't need `@Nested`
     @Test
     public void test() {
     }
@@ -45,7 +45,7 @@ public void test() {
     }
   }
 
-  public abstract class Test7 { // COMPLIANT: Abstract inner test classes don't need `@Nested`
+  public abstract class Test7 { // COMPLIANT: Abstract nested test classes don't need `@Nested`
     @Test
     public void test() {
     }

java/ql/test/query-tests/Likely Bugs/Frameworks/JUnit/JUnit5NonStaticInnerClassMissingNestedAnnotation.expected

@@ -1 +1 @@
-| AnnotationTest.java:13:16:13:20 | Test2 | This JUnit5 inner test class lacks a '@Nested' annotation. |
+| AnnotationTest.java:13:16:13:20 | Test2 | This JUnit 5 inner test class lacks a '@Nested' annotation. |