#1514: Add a test case for ClassTraverser

By: DerFrZocker <derrieple@gmail.com>

paper-server/src/test/java/org/bukkit/craftbukkit/util/ClassTraverserTest.java

@@ -0,0 +1,123 @@
+package org.bukkit.craftbukkit.util;
+
+import static org.junit.jupiter.api.Assertions.*;
+import java.io.Serializable;
+import java.lang.annotation.Annotation;
+import java.lang.constant.Constable;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Stream;
+import org.bukkit.support.environment.Normal;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+@Normal
+public class ClassTraverserTest {
+
+    public static Stream<Arguments> data() {
+        return Stream.of(
+                Arguments.of(FirstTest.class, List.of(
+                        FirstTest.class,
+                        Object.class
+                )),
+                Arguments.of(SecondTest.class, List.of(
+                        SecondTest.class,
+                        SecondTestClass.class,
+                        SecondTestInterface.class,
+                        SecondTestInterface2.class,
+                        Object.class
+                )),
+                Arguments.of(ThirdTestInterface.class, List.of(
+                        ThirdTestInterface.class,
+                        ThirdTestInterface2.class
+                )),
+                Arguments.of(FourthTest.class, List.of(
+                        FourthTest.class,
+                        FourthTestInterface.class,
+                        Record.class,
+                        Object.class
+                )),
+                Arguments.of(FifthTest.class, List.of(
+                        FifthTest.class,
+                        Enum.class,
+                        Constable.class,
+                        Comparable.class,
+                        Serializable.class,
+                        Object.class
+                )),
+                Arguments.of(SixthTest.class, List.of(
+                        SixthTest.class,
+                        Annotation.class
+                ))
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("data")
+    public void test(Class<?> clazz, List<Class<?>> expected) {
+        ClassTraverser classTraverser = new ClassTraverser(clazz);
+        List<Class<?>> result = new ArrayList<>();
+
+        while (classTraverser.hasNext()) {
+            result.add(classTraverser.next());
+        }
+
+        assertEquals(expected.size(), result.size(), String.format("""
+                Expected classes:
+                %s
+
+                Result:
+                %s
+                """, expected, result));
+
+        for (Class<?> got : expected) {
+            assertTrue(result.contains(got), String.format("""
+                    Result classes:
+                    %s
+
+                    Does not contain class:
+                    %s
+                    """, result, got));
+        }
+    }
+
+    // First Test
+    private class FirstTest {
+    }
+
+    // Second Test
+    private class SecondTest extends SecondTestClass implements SecondTestInterface {
+    }
+
+    private class SecondTestClass implements SecondTestInterface, SecondTestInterface2 {
+    }
+
+    private interface SecondTestInterface extends SecondTestInterface2 {
+    }
+
+    private interface SecondTestInterface2 {
+    }
+
+    // Third Test
+    private interface ThirdTestInterface extends ThirdTestInterface2 {
+    }
+
+    private interface ThirdTestInterface2 {
+    }
+
+    // Fourth Test
+    private record FourthTest() implements FourthTestInterface {
+    }
+
+    private interface FourthTestInterface {
+    }
+
+    // Fifth Test
+    private enum FifthTest {
+    }
+
+    // Sixth Test
+    private @interface SixthTest {
+    }
+}