fix(tests): adapt to Log4J2LoggingSystem refactor

This commit updates the test suite to align with the recent `Log4J2LoggingSystem` changes: * Each test now uses its own `LoggerContext`, making manual reset of previous state unnecessary. * Removes tests for `getStandardConfigLocation()` and `getSpringConfigLocation()`, as these methods are now deprecated no-ops and no longer attempt to infer configuration files based on classpath contents. * Removes a test for `UrlConfigurationFactory`, which is no longer in use. Signed-off-by: Piotr P. Karwasz <piotr@github.copernik.eu>

Author: ppkarwasz

core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java

@@ -40,7 +40,6 @@
 import org.apache.logging.log4j.core.filter.DenyAllFilter;
 import org.apache.logging.log4j.core.util.NameUtil;
 import org.apache.logging.log4j.jul.Log4jBridgeHandler;
-import org.apache.logging.log4j.spi.LoggerContextFactory;
 import org.apache.logging.log4j.status.StatusConsoleListener;
 import org.apache.logging.log4j.status.StatusLogger;
 import org.apache.logging.log4j.util.PropertiesUtil;
@@ -110,9 +109,28 @@ public class Log4J2LoggingSystem extends AbstractLoggingSystem {
 
 private final LoggerContext loggerContext;
 
-private Log4J2LoggingSystem(ClassLoader classLoader, org.apache.logging.log4j.spi.LoggerContext loggerContext) {
+/**
+ * Create a new {@link Log4J2LoggingSystem} instance.
+ * @param classLoader the class loader to use.
+ * @param loggerContext the {@link LoggerContext} to use.
+ */
+Log4J2LoggingSystem(ClassLoader classLoader, LoggerContext loggerContext) {
 super(classLoader);
-this.loggerContext = (LoggerContext) loggerContext;
+this.loggerContext = loggerContext;
+}
+
+/**
+ * Create a new {@link Log4J2LoggingSystem} instance.
+ * @param classLoader the class loader to use
+ * @return a new {@link Log4J2LoggingSystem} instance
+ * @throws IllegalStateException if Log4j Core is not the active Log4j API provider.
+ */
+private static Log4J2LoggingSystem createLoggingSystem(ClassLoader classLoader) {
+org.apache.logging.log4j.spi.LoggerContext loggerContext = LogManager.getContext(classLoader, false);
+if (loggerContext instanceof LoggerContext) {
+return new Log4J2LoggingSystem(classLoader, (LoggerContext) loggerContext);
+}
+throw new IllegalStateException("Log4j Core is not the active Log4j API provider");
 }
 
 /**
@@ -136,7 +154,8 @@ protected String[] getStandardConfigLocations() {
 ConfigurationFactory configurationFactory = ConfigurationFactory.getInstance();
 Configuration springConfiguration = configurationFactory.getConfiguration(getLoggerContext(), "-spring", null,
 getClassLoader());
-return getConfigLocation(springConfiguration);
+String configLocation = getConfigLocation(springConfiguration);
+return (configLocation != null && configLocation.contains("-spring")) ? configLocation : null;
 }
 
 private @Nullable String getConfigLocation(Configuration configuration) {
@@ -460,7 +479,7 @@ public void cleanUp() {
 return configuration.getLoggers().get(name);
 }
 
-private LoggerContext getLoggerContext() {
+LoggerContext getLoggerContext() {
 return this.loggerContext;
 }
 
@@ -496,20 +515,22 @@ protected String getDefaultLogCorrelationPattern() {
  * {@link LoggingSystemFactory} that returns {@link Log4J2LoggingSystem} if possible.
  */
 @Order(0)
-public static class Factory extends LogManager implements LoggingSystemFactory {
-
-private static final String FQCN = Factory.class.getName();
+public static class Factory implements LoggingSystemFactory {
 
 private static final String LOG4J_CORE_CONTEXT_FACTORY = "org.apache.logging.log4j.core.impl.Log4jContextFactory";
 
+private static final boolean PRESENT = ClassUtils.isPresent(LOG4J_CORE_CONTEXT_FACTORY,
+Factory.class.getClassLoader());
+
 @Override
 public @Nullable LoggingSystem getLoggingSystem(ClassLoader classLoader) {
-LoggerContextFactory contextFactory = getFactory();
-// At the same time, we check that Log4j Core is present and that it is the
-// active
-// implementation.
-if (LOG4J_CORE_CONTEXT_FACTORY.equals(contextFactory.getClass().getName())) {
-return new Log4J2LoggingSystem(classLoader, contextFactory.getContext(FQCN, classLoader, null, false));
+if (PRESENT) {
+try {
+return createLoggingSystem(classLoader);
+}
+catch (IllegalStateException ex) {
+// Log4j Core is not the active Log4j API provider
+}
 }
 return null;
 }