CRUNCH-419 Writables.registerComparable does not actually register the W...

crunch-core/src/main/java/org/apache/crunch/types/writable/Writables.java

@@ -122,6 +122,7 @@ public static void registerComparable(Class<? extends WritableComparable> clazz,
     if (WRITABLE_CODES.containsKey(code)) {
       throw new IllegalArgumentException("Already have writable class assigned to code = " + code);
     }
+    WRITABLE_CODES.put(code, clazz);
   }
 
   private static final String WRITABLE_COMPARABLE_CODES = "crunch.writable.comparable.codes";

crunch-core/src/test/java/org/apache/crunch/types/writable/WritablesTest.java

@@ -42,7 +42,7 @@
 import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.NullWritable;
 import org.apache.hadoop.io.Text;
-import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.io.WritableUtils;
 import org.junit.Test;
 
@@ -172,7 +172,7 @@ public void testTupleN() throws Exception {
     testInputOutputFn(wt, j, w);
   }
 
-  protected static class TestWritable implements Writable {
+  protected static class TestWritable implements WritableComparable<TestWritable> {
     String left;
     int right;
 
@@ -207,6 +207,13 @@ public boolean equals(Object obj) {
       return true;
     }
 
+    @Override
+    public int compareTo(TestWritable o) {
+      int cmp = left.compareTo(o.left);
+      if (cmp != 0)
+        return cmp;
+      return Integer.valueOf(right).compareTo(Integer.valueOf(o.right));
+    }
   }
 
   @Test
@@ -236,6 +243,12 @@ public void testRegister() throws Exception {
     assertSame(Writables.records(TestWritable.class), wt);
   }
 
+  @Test
+  public void testRegisterComparable() throws Exception {
+    Writables.registerComparable(TestWritable.class);
+    assertNotNull(Writables.WRITABLE_CODES.inverse().get(TestWritable.class));
+  }
+
   @SuppressWarnings({ "unchecked", "rawtypes" })
   protected static void testInputOutputFn(PType ptype, Object java, Object writable) {
     ptype.getInputMapFn().initialize();