adapt test to SLF4J version 2.0.16

Signed-off-by: Ceki Gulcu <ceki@qos.ch>

logback-classic/src/test/java/ch/qos/logback/classic/spi/InvocationTest.java

@@ -13,24 +13,27 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.slf4j.helpers.Reporter.SLF4J_INTERNAL_VERBOSITY_KEY;
 
 public class InvocationTest {
 
     private final PrintStream oldErr = System.err;
     final String loggerName = this.getClass().getName();
     StringPrintStream sps = new StringPrintStream(oldErr, true);
 
-    String CONNECTED_WITH_MESSAGE = "SLF4J(I): Connected with provider of type [ch.qos.logback.classic.spi.LogbackServiceProvider]";
+    String CONNECTED_WITH_MESSAGE = "SLF4J(D): Connected with provider of type [ch.qos.logback.classic.spi.LogbackServiceProvider]";
 
     @BeforeEach
     public void setUp() throws Exception {
+        System.setProperty(SLF4J_INTERNAL_VERBOSITY_KEY, "debug");
         System.setErr(sps);
     }
 
     @AfterEach
     public void tearDown() throws Exception {
         LoggerFactoryFriend.reset();
         System.setErr(oldErr);
+        System.clearProperty(SLF4J_INTERNAL_VERBOSITY_KEY);
     }
 
     // https://jira.qos.ch/browse/LOGBACK-1568 would have been prevented