Added unit tests and javadoc for Counter class.

Mage/src/main/java/mage/counters/Counter.java

@@ -28,64 +28,145 @@
 
 package mage.counters;
 
+import org.apache.log4j.Logger;
+
 import java.io.Serializable;
 
 /**
- *
  * @author BetaSteward_at_googlemail.com
  */
 public class Counter implements Serializable {
 
-    protected String name;
+    private static final Logger logger = Logger.getLogger(Counter.class);
+
+    protected final String name;
     protected int count;
 
-    public Counter(String name) {
+
+    /**
+     * Creates a {@link Counter} with the provided {@code name} and a default value of 1
+     *
+     * @param name the name of this counter.
+     */
+    public Counter(final String name) {
         this.name = name;
         this.count = 1;
     }
 
-    public Counter(String name, int count) {
+
+    /**
+     * Creates a {@link Counter} with the provided {@code name} and {@code count}
+     *
+     * @param name  the name of this counter.
+     * @param count the value of this counter.
+     */
+    public Counter(final String name, final int count) {
         this.name = name;
         this.count = count;
     }
 
+
+    /**
+     * Creates a {@link Counter} from an existing {@link Counter} object.
+     *
+     * @param counter the {@link Counter} to create a copy from.
+     */
     public Counter(final Counter counter) {
         this.name = counter.name;
         this.count = counter.count;
     }
 
-    public void add() {
+    /**
+     * Increases the {@code count} by 1
+     */
+    public void increase() {
         count++;
     }
 
+    /**
+     * Adds the passed in {@code amount} to the {@code count}
+     *
+     * @param amount the value to add to the {@code count}
+     */
     public void add(int amount) {
         count += amount;
     }
 
-    public void remove() {
+
+    /**
+     * Decreases the {@code count} by one. Will not allow the count to be less than 0.
+     * If an attempt is made to make the count be less than zero, the call will be logged.
+     */
+    public void decrease() {
         if (count > 0) {
             count--;
+        } else {
+            logger.warn("An attempt was made to set the counter '" + name +
+                    "' to less than 0. Setting to 0.");
         }
     }
 
+
+    /**
+     * Decreases the {@code count} by tne passed in {@code amount}. Will not allow the count
+     * to be less than 0. If an attempt is made to make the count be less than zero, the call will be logged.
+     */
     public void remove(int amount) {
         if (count > amount) {
             count -= amount;
-        }
-        else {
+        } else {
+            logger.warn("An attempt was made to set the counter '" + name +
+                    "' to less than 0. Setting to 0.");
             count = 0;
         }
     }
 
+
+    /**
+     * Returns the name of this {@link Counter}
+     *
+     * @return the name of this {@link Counter}
+     */
     public String getName() {
         return name;
     }
 
+    /**
+     * Returns the count of this {@link Counter}
+     *
+     * @return the count of this {@link Counter}
+     */
     public int getCount() {
         return count;
     }
 
+    /**
+     * Returns a deep copy of this object.
+     *
+     * @return a deep copy of this object.
+     */
     public Counter copy() {
         return new Counter(this);
     }
+
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Counter counter = (Counter) o;
+
+        if (count != counter.count) return false;
+        return !(name != null ? !name.equals(counter.name) : counter.name != null);
+
+    }
+
+
+    @Override
+    public int hashCode() {
+        int result = name != null ? name.hashCode() : 0;
+        result = 31 * result + count;
+        return result;
+    }
 }

Mage/src/main/java/mage/counters/Counters.java

@@ -56,7 +56,7 @@ public class Counters extends HashMap<String, Counter> implements Serializable {
         if (!this.containsKey(name)) {
             this.put(name, new Counter(name));
         }
-        this.get(name).add();
+        this.get(name).increase();
         }        
 
     public void addCounter(String name, int amount) {

Mage/src/test/java/mage/counters/CounterTest.java

@@ -0,0 +1,135 @@
+package mage.counters;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Custom unit tests for {@link Counter}
+ */
+public class CounterTest {
+
+    private Counter counter;
+
+    @Before
+    public void setUp() {
+        counter = new Counter("test", 1);
+    }
+
+
+    @Test
+    public void shouldIncreaseCounter() {
+        // given
+
+        // when
+        counter.increase();
+
+        // then
+        assertEquals(2, counter.getCount());
+        assertEquals("test", counter.getName());
+    }
+
+
+    @Test
+    public void shouldAddMana() {
+        // given
+
+        // when
+        counter.add(5);
+
+        // then
+        assertEquals(6, counter.getCount());
+    }
+
+
+    @Test
+    public void shouldDecreaseCounter() {
+        // given
+
+
+        // when
+        counter.decrease();
+
+        // then
+        assertEquals(0, counter.getCount());
+    }
+
+
+    @Test
+    public void shouldNotDecreaseToLessThanZero() {
+        // given
+
+        // when
+        counter.decrease();
+        counter.decrease();
+
+        // then
+        assertEquals(0, counter.getCount());
+    }
+
+
+    @Test
+    public void shouldRemoveCounters() {
+        // given
+
+
+        // when
+        counter.remove(1);
+
+        // then
+        assertEquals(0, counter.getCount());
+    }
+
+
+    @Test
+    public void shouldNotRemoveMoreCountersThanAvailable() {
+        // given
+
+        // when
+        counter.remove(10);
+
+        // then
+        assertEquals(0, counter.getCount());
+    }
+
+
+    @Test
+    public void shouldReturnCopy() {
+        // given
+
+        // when
+        Counter copy = counter.copy();
+
+        // then
+        assertEquals(copy, counter);
+        assertFalse(copy == counter);
+    }
+
+
+    @Test
+    public void shouldCreateCounterFromCounter() {
+        // given
+
+        // when
+        Counter copy = new Counter(counter);
+
+        // then
+        assertEquals(1, copy.getCount());
+        assertEquals("test", copy.getName());
+    }
+
+
+    @Test
+    public void shouldCreatDefaultCounter() {
+        // given
+
+
+        // when
+        Counter defaultCounter = new Counter("default");
+
+        // then
+        assertEquals(1, defaultCounter.getCount());
+        assertEquals("default", defaultCounter.getName());
+    }
+}