in-memory logger for use in tests, with tests

core/src/test/java/org/jclouds/logging/BufferLogger.java

@@ -0,0 +1,154 @@
+package org.jclouds.logging;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.logging.Level;
+
+import junit.framework.AssertionFailedError;
+
+import org.jclouds.logging.BaseLogger;
+
+import com.google.common.base.Predicate;
+
+/** A logger implementation for use in testing; all log messages are remembered, \
+ * but not written anywhere. The messages can then be inspected {@link #getMessages()}
+ * or certain assertions applied (see assertXxx methods on these instances) */
+public class BufferLogger extends BaseLogger {
+
+   final String category;
+   Level level = Level.INFO;
+   List<Record> messages = Collections.synchronizedList(new ArrayList<Record>());
+
+   public static class Record {
+      Level level;
+      String message;
+      Throwable trace;
+      public Record(Level level, String message, Throwable trace) {
+         this.level = level;
+         this.message = message;
+         this.trace = trace;
+      }
+      public Level getLevel() {
+         return level;
+      }
+      public String getMessage() {
+         return message;
+      }
+      public Throwable getTrace() {
+         return trace;
+      }
+   }
+
+   
+   public BufferLogger(String category) {
+      this.category = category;
+   }
+   
+   public List<Record> getMessages() {
+      return messages;
+   }
+   
+   /** throws AssertionFailedError if the log does not contain the indicated fragment;
+    * otherwise returns a record which does satisfy the constraint 
+    */
+   public Record assertLogContains(String fragment) {
+      for (Record r: messages) {
+         if (r.getMessage()!=null && r.getMessage().contains(fragment)) return r;
+      }
+      throw new AssertionFailedError("log did not contain expected '"+fragment+"'");
+   }
+   /** fails if log _does_ contain the indicated fragment */
+   public void assertLogDoesntContain(String fragment) {
+      for (Record r: messages) {
+         if (r.getMessage()!=null && r.getMessage().contains(fragment)) 
+            throw new AssertionFailedError("log contained unexpected '"+fragment+"'");
+      }
+   }
+
+   /** throws AssertionFailedError if the log does not contain the indicated fragment;
+    * otherwise returns a record which does satisfy the constraint 
+    */
+   public Record assertLogContains(Predicate<Record> test) {
+      for (Record r: messages) {
+         if (r.getMessage()!=null && test.apply(r)) return r;
+      }
+      throw new AssertionFailedError("log did not contain any records satisfying expected predicate");      
+   }
+   
+   @Override
+   public String getCategory() {
+      return category;
+   }
+
+   public void setLevel(Level level) {
+      this.level = level;
+   }
+   public void setAllLevelsEnabled() {
+      level = Level.ALL;
+   }
+   public void setAllLevelsDisabled() {
+      level = Level.OFF;
+   }
+   
+   @Override
+   public boolean isTraceEnabled() {
+      return level.intValue() <= Level.FINER.intValue();
+   }
+   @Override
+   public boolean isDebugEnabled() {
+      return level.intValue() <= Level.FINE.intValue();
+   }
+
+   @Override
+   public boolean isInfoEnabled() {
+      return level.intValue() <= Level.INFO.intValue();
+   }
+
+   @Override
+   public boolean isWarnEnabled() {
+      return level.intValue() <= Level.WARNING.intValue();
+   }
+
+   @Override
+   public boolean isErrorEnabled() {
+      return level.intValue() <= Level.SEVERE.intValue();
+   }
+   
+   
+   @Override
+   protected void logError(String message, Throwable e) {
+      getMessages().add(new Record(Level.SEVERE, message, e));
+   }
+
+   @Override
+   protected void logError(String message) {
+      getMessages().add(new Record(Level.SEVERE, message, null));
+   }
+
+   @Override
+   protected void logWarn(String message, Throwable e) {
+      getMessages().add(new Record(Level.WARNING, message, e));   
+   }
+
+   @Override
+   protected void logWarn(String message) {
+      getMessages().add(new Record(Level.WARNING, message, null));   
+   }
+
+   @Override
+   protected void logInfo(String message) {
+      getMessages().add(new Record(Level.INFO, message, null));   
+   }
+
+   @Override
+   protected void logDebug(String message) {
+      getMessages().add(new Record(Level.FINE, message, null));   
+   }
+
+   @Override
+   protected void logTrace(String message) {
+      getMessages().add(new Record(Level.FINER, message, null));   
+   }
+
+}

core/src/test/java/org/jclouds/logging/BufferLoggerTest.java

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+package org.jclouds.logging;
+
+import java.util.logging.Level;
+
+import org.jclouds.logging.BufferLogger.Record;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+@Test
+public class BufferLoggerTest {
+
+   public void testLogCapturesRightMessages() {
+      BufferLogger b = new BufferLogger("foo");
+      b.setLevel(Level.INFO);
+      b.info("hi 1");
+      b.error(new Throwable("check"), "hi 2");
+      b.debug("hi 3 nope");
+      
+      Record r;
+      r = b.assertLogContains("hi 1");
+      Assert.assertEquals(Level.INFO, r.getLevel());
+      Assert.assertNull(r.getTrace());
+      
+      r = b.assertLogContains("hi 2");
+      Assert.assertEquals(Level.SEVERE, r.getLevel());
+      Assert.assertEquals(r.getTrace().getMessage(), "check");
+      
+      b.assertLogDoesntContain("hi 3");
+   }
+   
+}