CompositeLog respects log level changes at runtime

Closes gh-28477

spring-core/src/test/java/org/springframework/core/log/CompositeLogTests.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.log;
+
+import java.util.Arrays;
+
+import org.apache.commons.logging.Log;
+import org.junit.jupiter.api.Test;
+
+import static org.mockito.BDDMockito.when;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+
+/**
+ * Unit tests for {@link CompositeLog}.
+ * @author Rossen Stoyanchev
+ */
+public class CompositeLogTests {
+
+	private final Log logger1 = mock(Log.class);
+
+	private final Log logger2 = mock(Log.class);
+
+	private final CompositeLog compositeLog = new CompositeLog(Arrays.asList(logger1, logger2));
+
+
+	@Test
+	void useFirstLogger() {
+		when(logger1.isInfoEnabled()).thenReturn(true);
+		when(logger2.isInfoEnabled()).thenReturn(true);
+
+		this.compositeLog.info("info message");
+
+		verify(this.logger1).isInfoEnabled();
+		verify(this.logger1).info("info message");
+
+		verifyNoMoreInteractions(this.logger1);
+		verifyNoMoreInteractions(this.logger2);
+	}
+
+	@Test
+	void useSecondLogger() {
+		when(logger1.isInfoEnabled()).thenReturn(false);
+		when(logger2.isInfoEnabled()).thenReturn(true);
+
+		this.compositeLog.info("info message");
+
+		verify(this.logger1).isInfoEnabled();
+		verify(this.logger2).isInfoEnabled();
+		verify(this.logger2).info("info message");
+
+		verifyNoMoreInteractions(this.logger1);
+		verifyNoMoreInteractions(this.logger2);
+	}
+
+	@Test
+	void useNeitherLogger() {
+		when(logger1.isInfoEnabled()).thenReturn(false);
+		when(logger2.isInfoEnabled()).thenReturn(false);
+
+		this.compositeLog.info("info message");
+
+		verify(this.logger1).isInfoEnabled();
+		verify(this.logger2).isInfoEnabled();
+
+		verifyNoMoreInteractions(this.logger1);
+		verifyNoMoreInteractions(this.logger2);
+	}
+
+}