#502 Adjusted tests for logger introduction

state/src/test/java/com/iluwatar/state/MammothTest.java

@@ -22,17 +22,19 @@
  */
 package com.iluwatar.state;
 
+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.InOrder;
-import org.mockito.Mockito;
+import org.slf4j.LoggerFactory;
 
-import java.io.PrintStream;
+import java.util.LinkedList;
+import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
-import static org.mockito.Mockito.mock;
 
 /**
  * Date: 12/29/15 - 8:27 PM
@@ -41,31 +43,16 @@ import static org.mockito.Mockito.mock;
  */
 public class MammothTest {
 
-  /**
-   * The mocked standard out {@link PrintStream}, required since some actions don't have any
-   * influence on accessible objects, except for writing to std-out using {@link System#out}
-   */
-  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();
   }
 
-  /**
-   * Removed the mocked std-out {@link PrintStream} again from the {@link System} class
-   */
   @After
   public void tearDown() {
-    System.setOut(this.stdOutOrig);
+    appender.stop();
   }
 
   /**
@@ -74,28 +61,27 @@ public class MammothTest {
    */
   @Test
   public void testTimePasses() {
-    final InOrder inOrder = Mockito.inOrder(this.stdOutMock);
     final Mammoth mammoth = new Mammoth();
 
     mammoth.observe();
-    inOrder.verify(this.stdOutMock).println("The mammoth is calm and peaceful.");
-    inOrder.verifyNoMoreInteractions();
+    assertEquals("The mammoth is calm and peaceful.", appender.getLastMessage());
+    assertEquals(1 , appender.getLogSize());
 
     mammoth.timePasses();
-    inOrder.verify(this.stdOutMock).println("The mammoth gets angry!");
-    inOrder.verifyNoMoreInteractions();
+    assertEquals("The mammoth gets angry!", appender.getLastMessage());
+    assertEquals(2 , appender.getLogSize());
 
     mammoth.observe();
-    inOrder.verify(this.stdOutMock).println("The mammoth is furious!");
-    inOrder.verifyNoMoreInteractions();
+    assertEquals("The mammoth is furious!", appender.getLastMessage());
+    assertEquals(3 , appender.getLogSize());
 
     mammoth.timePasses();
-    inOrder.verify(this.stdOutMock).println("The mammoth calms down.");
-    inOrder.verifyNoMoreInteractions();
+    assertEquals("The mammoth calms down.", appender.getLastMessage());
+    assertEquals(4 , appender.getLogSize());
 
     mammoth.observe();
-    inOrder.verify(this.stdOutMock).println("The mammoth is calm and peaceful.");
-    inOrder.verifyNoMoreInteractions();
+    assertEquals("The mammoth is calm and peaceful.", appender.getLastMessage());
+    assertEquals(5 , appender.getLogSize());
 
   }
 
@@ -109,4 +95,26 @@ public class MammothTest {
     assertEquals("The mammoth", toString);
   }
 
-}
+  private class InMemoryAppender extends AppenderBase<ILoggingEvent> {
+    private List<ILoggingEvent> log = new LinkedList<>();
+
+    public InMemoryAppender() {
+      ((Logger) LoggerFactory.getLogger("root")).addAppender(this);
+      start();
+    }
+
+    @Override
+    protected void append(ILoggingEvent eventObject) {
+      log.add(eventObject);
+    }
+
+    public int getLogSize() {
+      return log.size();
+    }
+
+    public String getLastMessage() {
+      return log.get(log.size() - 1).getFormattedMessage();
+    }
+  }
+
+}