Add test cases to enhance coverage for Sets, Lists, Maps, and ReflectionUtils

Co-authored-by: mercyblitz <533114+mercyblitz@users.noreply.github.com>

Author: Copilot

microsphere-java-core/src/test/java/io/microsphere/collection/ListsTest.java

@@ -7,6 +7,7 @@
 import static io.microsphere.collection.Lists.ofList;
 import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * {@link Lists} Test
@@ -77,4 +78,12 @@ void testOfList() {
         assertEquals(emptyList(), ofList(TEST_NULL_OBJECT_ARRAY));
         assertEquals(of(1, 2, 3), ofList(1, 2, 3));
     }
+
+    @Test
+    void testOfListImmutability() {
+        assertThrows(UnsupportedOperationException.class, () -> ofList().add("x"));
+        assertThrows(UnsupportedOperationException.class, () -> ofList(1).add(2));
+        assertThrows(UnsupportedOperationException.class, () -> ofList(1, 2).remove(0));
+        assertThrows(UnsupportedOperationException.class, () -> ofList(1, 2, 3).clear());
+    }
 }

microsphere-java-core/src/test/java/io/microsphere/collection/MapsTest.java

@@ -11,6 +11,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * {@link Maps} Test
@@ -186,4 +187,22 @@ void testMapOfOnEmptyEntries() {
         Map map = Maps.ofMap(new Map.Entry[0]);
         assertSame(emptyMap(), map);
     }
+
+    @Test
+    void testOfMapOnSingleEntry() {
+        Map.Entry<String, Integer> entry = ofEntry("A", 1);
+        Map<String, Integer> map = Maps.ofMap(entry);
+        assertEquals(1, map.size());
+        assertEquals(1, map.get("A"));
+        assertNull(map.get("B"));
+        assertOfMap(map);
+    }
+
+    @Test
+    void testOfMapImmutability() {
+        assertThrows(UnsupportedOperationException.class, () -> ofMap().put("k", "v"));
+        assertThrows(UnsupportedOperationException.class, () -> ofMap("A", 1).put("B", 2));
+        assertThrows(UnsupportedOperationException.class, () -> ofMap("A", 1, "B", 2).remove("A"));
+        assertThrows(UnsupportedOperationException.class, () -> ofMap("A", 1, "B", 2, "C", 3).clear());
+    }
 }

microsphere-java-core/src/test/java/io/microsphere/collection/SetsTest.java

@@ -7,6 +7,7 @@
 import static io.microsphere.collection.Sets.ofSet;
 import static java.util.Collections.emptySet;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * {@link Sets} Test
@@ -77,4 +78,12 @@ void testOfSet() {
         assertEquals(emptySet(), ofSet(TEST_NULL_OBJECT_ARRAY));
         assertEquals(of(1, 2, 3), ofSet(1, 2, 3));
     }
+
+    @Test
+    void testOfSetImmutability() {
+        assertThrows(UnsupportedOperationException.class, () -> ofSet().add("x"));
+        assertThrows(UnsupportedOperationException.class, () -> ofSet(1).add(2));
+        assertThrows(UnsupportedOperationException.class, () -> ofSet(1, 2).remove(1));
+        assertThrows(UnsupportedOperationException.class, () -> ofSet(1, 2, 3).clear());
+    }
 }

microsphere-java-core/src/test/java/io/microsphere/convert/multiple/StringToIterableConverterTest.java

@@ -36,8 +36,12 @@
 /**
  * {@link StringToIterableConverter} Test
  *
+ * <p>Tests the abstract {@link StringToIterableConverter} behavior using
+ * {@link StringToCollectionConverter} as the concrete implementation.</p>
+ *
  * @author <a href="mailto:mercyblitz@gmail.com">Mercy</a>
  * @see StringToIterableConverter
+ * @see StringToCollectionConverter
  * @since 1.0.0
  */
 class StringToIterableConverterTest {

microsphere-java-core/src/test/java/io/microsphere/reflect/ReflectionUtilsTest.java

@@ -10,6 +10,12 @@
 import static io.microsphere.collection.Lists.ofList;
 import static io.microsphere.reflect.ReflectionUtils.INACCESSIBLE_OBJECT_EXCEPTION_CLASS;
 import static io.microsphere.reflect.ReflectionUtils.INACCESSIBLE_OBJECT_EXCEPTION_CLASS_NAME;
+import static io.microsphere.reflect.ReflectionUtils.STACK_WALKER_CLASS;
+import static io.microsphere.reflect.ReflectionUtils.STACK_WALKER_CLASS_NAME;
+import static io.microsphere.reflect.ReflectionUtils.STACK_WALKER_STACK_FRAME_CLASS;
+import static io.microsphere.reflect.ReflectionUtils.STACK_WALKER_STACK_FRAME_CLASS_NAME;
+import static io.microsphere.reflect.ReflectionUtils.SUN_REFLECT_REFLECTION_CLASS;
+import static io.microsphere.reflect.ReflectionUtils.SUN_REFLECT_REFLECTION_CLASS_NAME;
 import static io.microsphere.reflect.ReflectionUtils.getCallerClass;
 import static io.microsphere.reflect.ReflectionUtils.getCallerClassInSunReflectReflection;
 import static io.microsphere.reflect.ReflectionUtils.getCallerClassName;
@@ -28,6 +34,7 @@
 import static java.util.Arrays.asList;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -144,6 +151,49 @@ void testIsInaccessibleObjectException() {
         assertTrue(isInaccessibleObjectException(INACCESSIBLE_OBJECT_EXCEPTION_CLASS_NAME));
     }
 
+    @Test
+    void testReadFieldsAsMapOnNull() {
+        assertTrue(readFieldsAsMap(null).isEmpty());
+    }
+
+    @Test
+    void testConstants() {
+        assertEquals("sun.reflect.Reflection", SUN_REFLECT_REFLECTION_CLASS_NAME);
+        assertEquals("java.lang.StackWalker", STACK_WALKER_CLASS_NAME);
+        assertEquals("java.lang.StackWalker$StackFrame", STACK_WALKER_STACK_FRAME_CLASS_NAME);
+        assertEquals("java.lang.reflect.InaccessibleObjectException", INACCESSIBLE_OBJECT_EXCEPTION_CLASS_NAME);
+    }
+
+    @Test
+    void testStackWalkerClassAvailability() {
+        if (testCurrentJavaVersion("<", JAVA_VERSION_9)) {
+            assertNull(STACK_WALKER_CLASS);
+            assertNull(STACK_WALKER_STACK_FRAME_CLASS);
+        } else {
+            assertNotNull(STACK_WALKER_CLASS);
+            assertNotNull(STACK_WALKER_STACK_FRAME_CLASS);
+        }
+    }
+
+    @Test
+    void testSunReflectReflectionClassAvailability() {
+        boolean supported = isSupportedSunReflectReflection();
+        if (supported) {
+            assertNotNull(SUN_REFLECT_REFLECTION_CLASS);
+        }
+        // On JDK 9+, sun.reflect.Reflection#getCallerClass(int) was removed,
+        // so isSupportedSunReflectReflection() returns false even though the class may exist
+    }
+
+    @Test
+    void testGetCallerClassInSunReflectReflectionWithOffset() {
+        if (isSupportedSunReflectReflection()) {
+            assertNotNull(getCallerClassInSunReflectReflection(0));
+        } else {
+            assertNull(getCallerClassInSunReflectReflection(0));
+        }
+    }
+
     static class T extends Data {
 
         private T self;