add test and fix

dspace-api/src/main/java/org/dspace/content/Bundle.java

@@ -126,7 +126,7 @@ public class Bundle extends DSpaceObject implements DSpaceObjectLegacySupport {
      * Unset the primary bitstream ID of the bundle
      */
     public void unsetPrimaryBitstreamID() {
-        primaryBitstream = null;
+        setPrimaryBitstreamID(null);
     }
 
     /**

dspace-api/src/test/java/org/dspace/content/BundleTest.java

@@ -513,6 +513,38 @@ public class BundleTest extends AbstractDSpaceObjectTest {
     }
 
 
+    /**
+     * Test removeBitstream method and also the unsetPrimaryBitstreamID method, of class Bundle.
+     */
+    @Test
+    public void testRemoveBitstreamAuthAndUnsetPrimaryBitstreamID() throws IOException, SQLException, AuthorizeException {
+        // Allow Item WRITE permissions
+        doNothing().when(authorizeServiceSpy).authorizeAction(context, item, Constants.WRITE);
+        // Allow Bundle ADD permissions
+        doNothing().when(authorizeServiceSpy).authorizeAction(context, b, Constants.ADD);
+        // Allow Bitstream WRITE permissions
+        doNothing().when(authorizeServiceSpy)
+                   .authorizeAction(any(Context.class), any(Bitstream.class), eq(Constants.WRITE));
+        // Allow Bitstream DELETE permissions
+        doNothing().when(authorizeServiceSpy)
+                   .authorizeAction(any(Context.class), any(Bitstream.class), eq(Constants.DELETE));
+
+
+        context.turnOffAuthorisationSystem();
+        //set a value different than default
+        File f = new File(testProps.get("test.bitstream").toString());
+        Bitstream bs = bitstreamService.create(context, new FileInputStream(f));
+        bundleService.addBitstream(context, b, bs);
+        b.setPrimaryBitstreamID(bs);
+        context.restoreAuthSystemState();
+
+        assertThat("testRemoveBitstreamAuthAndUnsetPrimaryBitstreamID 0", b.getPrimaryBitstream(), equalTo(bs));
+        //remove bitstream
+        bundleService.removeBitstream(context, b, bs);
+        //is -1 when not set
+        assertThat("testRemoveBitstreamAuthAndUnsetPrimaryBitstreamID 1", b.getPrimaryBitstream(), equalTo(null));
+    }
+
     /**
      * Test of update method, of class Bundle.
      */