Added a 'source' for commands that may be passed around in the context

src/test/java/net/minecraft/commands/context/CommandContextTest.java

@@ -3,32 +3,42 @@ package net.minecraft.commands.context;
 import net.minecraft.commands.arguments.IntegerArgumentType;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
 
 import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 
+@RunWith(MockitoJUnitRunner.class)
 public class CommandContextTest {
-    CommandContext context;
+    CommandContextBuilder<Object> builder;
+    @Mock Object source;
 
     @Before
     public void setUp() throws Exception {
-        context = new CommandContextBuilder().build();
+        builder = new CommandContextBuilder<Object>(source);
     }
 
     @Test(expected = IllegalArgumentException.class)
     public void testGetArgument_nonexistent() throws Exception {
-        context.getArgument("foo", Object.class);
+        builder.build().getArgument("foo", Object.class);
     }
 
     @Test(expected = IllegalArgumentException.class)
     public void testGetArgument_wrongType() throws Exception {
-        context = new CommandContextBuilder().withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
+        CommandContext<Object> context = builder.withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
         context.getArgument("foo", String.class);
     }
 
     @Test
     public void testGetArgument() throws Exception {
-        context = new CommandContextBuilder().withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
+        CommandContext<Object> context = builder.withArgument("foo", IntegerArgumentType.integer().parse("123")).build();
         assertThat(context.getArgument("foo", int.class).getResult(), is(123));
     }
+
+    @Test
+    public void testSource() throws Exception {
+        assertThat(builder.build().getSource(), is(source));
+    }
 }