Misc cleanup of LoggerTest.

src/test/java/com/jcraft/jsch/LoggerTest.java

@@ -1,56 +1,60 @@
 package com.jcraft.jsch;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import java.io.PrintWriter;
 import java.io.StringWriter;
-import java.util.LinkedList;
-import java.util.stream.Collectors;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 import org.junit.jupiter.api.Test;
 
-class LoggerTest {
-
+public class LoggerTest {
+
+  private final Exception testException = new Exception("dummy exception");
+
   @Test
-  void testLogWithCause() {
-    LinkedList<String> messages = new LinkedList<>();
+  public void testLogging() {
+    List<String> actualMessages = new ArrayList<>();
     boolean[] enabledResult = new boolean[1];
-    Logger logger = new Logger() {
-      @Override
-      public void log(int level, String message) {
-        messages.add(level + ":" + message);
-      }
-      @Override
-      public boolean isEnabled(int level) {
-        return enabledResult[0];
-      }
-    };
-
-    Exception ex = new Exception("dummy exception");
+    Logger logger =
+        new Logger() {
+          @Override
+          public void log(int level, String message) {
+            if (isEnabled(level)) {
+              actualMessages.add(level + ":" + message);
+            }
+          }
+
+          @Override
+          public boolean isEnabled(int level) {
+            return enabledResult[0];
+          }
+        };
+
+    actualMessages.clear();
+    enabledResult[0] = false;
+    logger.log(Logger.ERROR, "debug message");
+    logger.log(Logger.ERROR, "debug message with null cause", null);
+    logger.log(Logger.ERROR, "debug message with cause", testException);
+    assertEquals(Collections.emptyList(), actualMessages, "mismatch in logged messages");
+
     StringWriter sw = new StringWriter();
-    PrintWriter pw = new PrintWriter(sw);
-    ex.printStackTrace(pw);
-    String expectedTrace = sw.toString();
-
-    logger.log(Logger.ERROR, "some message", null);
-    logger.log(Logger.ERROR, "some message with trace", ex);
-    assertEquals("", getMessageLines(messages), "message mismatch");
-
-    enabledResult[0] = true;
-    logger.log(Logger.ERROR, "some message", null);
-    logger.log(Logger.ERROR, "some message with trace", ex);
-    assertEquals(
-        Logger.ERROR + ":some message\r\n" + 
-        Logger.ERROR + ":some message with trace" + System.lineSeparator() + 
-        expectedTrace +
-        "", getMessageLines(messages), "message mismatch");
-  }
-
-  static String getMessageLines(LinkedList<String> messages) {
-    try {
-      return messages.stream()
-          .collect(Collectors.joining("\r\n"));
-    }
-    finally {
-      messages.clear();
+    try (PrintWriter pw = new PrintWriter(sw, true)) {
+      testException.printStackTrace(pw);
     }
+    List<String> expectedMessages =
+        Arrays.asList(
+            Logger.ERROR + ":debug message",
+            Logger.ERROR + ":debug message with null cause",
+            Logger.ERROR + ":debug message with cause" + System.lineSeparator() + sw);
+
+    actualMessages.clear();
+    enabledResult[0] = true;
+    logger.log(Logger.ERROR, "debug message");
+    logger.log(Logger.ERROR, "debug message with null cause", null);
+    logger.log(Logger.ERROR, "debug message with cause", testException);
+    assertEquals(expectedMessages, actualMessages, "mismatch in logged messages");
   }
 }