#502 Adjusted tests for logger introduction

double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/InventoryTest.java

@@ -22,24 +22,23 @@
  */
 package com.iluwatar.doublechecked.locking;
 
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.AppenderBase;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.ArgumentCaptor;
+import org.slf4j.LoggerFactory;
 
-import java.io.PrintStream;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
-import static junit.framework.Assert.assertTrue;
 import static junit.framework.TestCase.assertEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Date: 12/10/15 - 9:34 PM
@@ -48,31 +47,16 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
  */
 public class InventoryTest {
 
-  /**
-   * The mocked standard out {@link PrintStream}, used to verify a steady increasing size of the
-   * {@link Inventory} while adding items from multiple threads concurrently
-   */
-  private final PrintStream stdOutMock = mock(PrintStream.class);
+  private InMemoryAppender appender;
 
-  /**
-   * Keep the original std-out so it can be restored after the test
-   */
-  private final PrintStream stdOutOrig = System.out;
-
-  /**
-   * Inject the mocked std-out {@link PrintStream} into the {@link System} class before each test
-   */
   @Before
   public void setUp() {
-    System.setOut(this.stdOutMock);
+    appender = new InMemoryAppender(Inventory.class);
   }
 
-  /**
-   * Removed the mocked std-out {@link PrintStream} again from the {@link System} class
-   */
   @After
   public void tearDown() {
-    System.setOut(this.stdOutOrig);
+    appender.stop();
   }
 
   /**
@@ -112,21 +96,32 @@ public class InventoryTest {
     assertNotNull(items);
     assertEquals(INVENTORY_SIZE, items.size());
 
-    // Capture all stdOut messages ...
-    final ArgumentCaptor<String> stdOutCaptor = ArgumentCaptor.forClass(String.class);
-    verify(this.stdOutMock, times(INVENTORY_SIZE)).println(stdOutCaptor.capture());
-
-    // ... verify if we got all 1000
-    final List<String> values = stdOutCaptor.getAllValues();
-    assertEquals(INVENTORY_SIZE, values.size());
+    assertEquals(INVENTORY_SIZE, appender.getLogSize());
 
     // ... and check if the inventory size is increasing continuously
-    for (int i = 0; i < values.size(); i++) {
-      assertNotNull(values.get(i));
-      assertTrue(values.get(i).contains("items.size()=" + (i + 1)));
+    for (int i = 0; i < items.size(); i++) {
+      assertTrue(appender.log.get(i).getFormattedMessage().contains("items.size()=" + (i + 1)));
     }
-
-    verifyNoMoreInteractions(this.stdOutMock);
   }
 
-}
+
+
+  private class InMemoryAppender extends AppenderBase<ILoggingEvent> {
+    private List<ILoggingEvent> log = new LinkedList<>();
+
+    public InMemoryAppender(Class clazz) {
+      ((Logger) LoggerFactory.getLogger(clazz)).addAppender(this);
+      start();
+    }
+
+    @Override
+    protected void append(ILoggingEvent eventObject) {
+      log.add(eventObject);
+    }
+
+    public int getLogSize() {
+      return log.size();
+    }
+  }
+
+}