Bael 9172 (#18546)

* Validate List

* Validate List

* Validate List

* Validate List

* Validate List

* Validate List

* BAEL-9172

* BAEL-9172

* BAEL-9172

---------

Co-authored-by: Neetika Khandelwal <[email protected]>

Author: Neetika23

logging-modules/logging-techniques/src/test/java/com/baeldung/logging/LoggerBreakUnitTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.logging;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class LoggerBreakUnitTest {
+
+    private Logger logger;
+    private ListAppender<ILoggingEvent> listAppender;
+
+    @BeforeEach
+    void setUp() {
+        logger = (Logger) LoggerFactory.getLogger(LoggerBreakUnitTest.class);
+        logger.setLevel(Level.INFO);
+
+        listAppender = new ListAppender<>();
+        listAppender.start();
+        logger.addAppender(listAppender);
+    }
+
+    @Test
+    void givenLogMessage_whenEmptyLineLogged_thenLogContainsBlankEntry() {
+        logger.info("Start process");
+        logger.info("");
+
+        List<ILoggingEvent> logs = listAppender.list;
+
+        assertEquals(2, logs.size());
+        assertEquals("Start process", logs.get(0)
+            .getFormattedMessage());
+        assertEquals("", logs.get(1)
+            .getFormattedMessage());
+    }
+
+    @Test
+    void givenLogMessage_whenUsingSystemLineSeparator_thenLogContainsPlatformSpecificLineBreak() {
+        logger.info("Processing done{}", System.lineSeparator());
+
+        List<ILoggingEvent> logs = listAppender.list;
+
+        assertEquals(1, logs.size());
+        assertTrue(logs.get(0)
+            .getFormattedMessage()
+            .endsWith(System.lineSeparator()));
+    }
+
+    @Test
+    void givenLogMessage_whenLineBreakIsConcatenated_thenLogSplitsCorrectly() {
+        logger.info("Processing done" + System.lineSeparator());
+
+        List<ILoggingEvent> logs = listAppender.list;
+
+        assertEquals(1, logs.size());
+        assertTrue(logs.get(0)
+            .getFormattedMessage()
+            .endsWith(System.lineSeparator()));
+    }
+
+    @Test
+    void givenLineSeparator_whenAppendedToLogMessages_thenLogEndsWithCorrectLineBreak() {
+        String newline = System.getProperty("line.separator");
+
+        logger.info("Processing started" + newline);
+        logger.info("Processing ended");
+
+        List<ILoggingEvent> logs = listAppender.list;
+
+        assertEquals(2, logs.size());
+
+        String firstMessage = logs.get(0)
+            .getFormattedMessage();
+        String secondMessage = logs.get(1)
+            .getFormattedMessage();
+
+        assertTrue(firstMessage.endsWith(newline), "First message should end with the system line separator");
+        assertEquals("Processing ended", secondMessage);
+    }
+}
+