Add test for empty logger parent name

Import assertNull and add an assertion verifying that Logging.getParentLoggerName("") returns null. This ensures the logging implementation correctly handles an empty logger name case in tests.

Author: mercyblitz

microsphere-logging-commons/src/test/java/io/microsphere/logging/LoggingTest.java

@@ -25,6 +25,7 @@
 import static io.microsphere.logging.DefaultLoggingLevelsResolverTest.JAVA_LOGGING_LEVELS;
 import static io.microsphere.logging.LoggingUtils.load;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 /**
  * {@link Logging} Test
@@ -80,6 +81,7 @@ void testGetParentLoggerName() {
         assertEquals("com.acme", this.logging.getParentLoggerName("com.acme.Test"));
         assertEquals("com", this.logging.getParentLoggerName("com.acme"));
         assertEquals("", this.logging.getParentLoggerName("com"));
+        assertNull(this.logging.getParentLoggerName(""));
     }
 
     @Test
@@ -92,4 +94,4 @@ void testGetPriority() {
         assertEquals(MAX_PRIORITY, this.logging.getPriority());
     }
 
-}
+}