HONEYCOMB-194 Raise unit test coverage of translation-util to 80%

Change-Id: I6689f6d1f6a4a1376465783dad2650f5137142d2
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>

11 files changed, 1046 insertions, 2 deletions

diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/DataObjects.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/DataObjects.java
index e602adbb6..f2f664efe 100644
--- a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/DataObjects.java
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/DataObjects.java
@@ -18,6 +18,8 @@ package io.fd.honeycomb.translate.util;
 
 import org.opendaylight.yangtools.yang.binding.ChildOf;
 import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.Identifiable;
+import org.opendaylight.yangtools.yang.binding.Identifier;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 public class DataObjects {
@@ -49,4 +51,14 @@ public class DataObjects {
             InstanceIdentifier<DataObject42> IID = DataObject4.IID.child(DataObject42.class);
         }
     }
+
+    public interface DataObjectK extends DataObject, Identifiable<DataObjectKey> {
+        InstanceIdentifier<DataObjectK> IID = InstanceIdentifier.create(DataObjectK.class);
+
+        interface DataObjectK1 extends DataObject, ChildOf<DataObjectK> {
+            InstanceIdentifier<DataObjectK1> IID = DataObjectK.IID.child(DataObjectK1.class);
+        }
+    }
+
+    public static class DataObjectKey implements Identifier<DataObjectK> {}
 }
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/RealtimeMappingContextTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/RealtimeMappingContextTest.java
new file mode 100644
index 000000000..1ee06c1b7
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/RealtimeMappingContextTest.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.controller.md.sal.binding.api.DataBroker;
+import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
+import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class RealtimeMappingContextTest {
+
+    @Mock
+    private DataBroker broker;
+    private RealtimeMappingContext ctx;
+    private InstanceIdentifier<DataObject> id = InstanceIdentifier.create(DataObject.class);
+    @Mock
+    private ReadOnlyTransaction readTx;
+    @Mock
+    private WriteTransaction writeTx;
+    @Mock
+    private DataObject data;
+    private TransactionCommitFailedException ex = new TransactionCommitFailedException("test fail");
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        ctx = new RealtimeMappingContext(broker);
+
+        when(broker.newReadOnlyTransaction()).thenReturn(readTx);
+        when(broker.newWriteOnlyTransaction()).thenReturn(writeTx);
+        when(writeTx.submit()).thenReturn(Futures.immediateCheckedFuture(null));
+    }
+
+    @Test
+    public void testRead() throws Exception {
+        final CheckedFuture<Optional<DataObject>, ReadFailedException> futureData =
+                Futures.immediateCheckedFuture(Optional.of((data)));
+        when(readTx.read(LogicalDatastoreType.OPERATIONAL, id)).thenReturn(futureData);
+
+        assertSame(ctx.read(id).get(), data);
+        verify(broker).newReadOnlyTransaction();
+        verify(readTx).read(LogicalDatastoreType.OPERATIONAL, id);
+
+        when(readTx.read(LogicalDatastoreType.OPERATIONAL, id)).thenReturn(Futures.immediateCheckedFuture(Optional.absent()));
+        assertFalse(ctx.read(id).isPresent());
+    }
+
+    @Test
+    public void testMerge() throws Exception {
+        ctx.merge(id, data);
+        verify(broker).newWriteOnlyTransaction();
+        verify(writeTx).merge(LogicalDatastoreType.OPERATIONAL, id, data);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testMergeFailure() throws Exception {
+        when(writeTx.submit()).thenReturn(Futures.immediateFailedCheckedFuture(ex));
+        ctx.merge(id, data);
+    }
+
+    @Test
+    public void testPut() throws Exception {
+        ctx.put(id, data);
+        verify(broker).newWriteOnlyTransaction();
+        verify(writeTx).put(LogicalDatastoreType.OPERATIONAL, id, data);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testPutFailure() throws Exception {
+        when(writeTx.submit()).thenReturn(Futures.immediateFailedCheckedFuture(ex));
+        ctx.put(id, data);
+    }
+
+    @Test
+    public void testDelete() throws Exception {
+        ctx.delete(id);
+        verify(broker).newWriteOnlyTransaction();
+        verify(writeTx).delete(LogicalDatastoreType.OPERATIONAL, id);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testDeleteFailure() throws Exception {
+        when(writeTx.submit()).thenReturn(Futures.immediateFailedCheckedFuture(ex));
+        ctx.delete(id);
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/TransactionMappingContextTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/TransactionMappingContextTest.java
new file mode 100644
index 000000000..2dcee889a
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/TransactionMappingContextTest.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.CheckedFuture;
+import com.google.common.util.concurrent.Futures;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.controller.md.sal.binding.api.ReadWriteTransaction;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class TransactionMappingContextTest {
+
+    private TransactionMappingContext ctx;
+    private InstanceIdentifier<DataObject> id = InstanceIdentifier.create(DataObject.class);
+    @Mock
+    private ReadWriteTransaction writeTx;
+    @Mock
+    private DataObject data;
+    private ReadFailedException ex = new ReadFailedException("test fail");
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        ctx = new TransactionMappingContext(writeTx);
+
+        when(writeTx.submit()).thenReturn(Futures.immediateCheckedFuture(null));
+    }
+
+    @Test
+    public void testRead() throws Exception {
+        final CheckedFuture<Optional<DataObject>, ReadFailedException> futureData =
+                Futures.immediateCheckedFuture(Optional.of((data)));
+        when(writeTx.read(LogicalDatastoreType.OPERATIONAL, id)).thenReturn(futureData);
+
+        assertSame(ctx.read(id).get(), data);
+        verify(writeTx).read(LogicalDatastoreType.OPERATIONAL, id);
+
+        when(writeTx.read(LogicalDatastoreType.OPERATIONAL, id)).thenReturn(Futures.immediateCheckedFuture(Optional.absent()));
+        assertFalse(ctx.read(id).isPresent());
+    }
+
+
+    @Test(expected = IllegalStateException.class)
+    public void testReadFailure() throws Exception {
+        final CheckedFuture<Optional<DataObject>, ReadFailedException> futureData =
+                Futures.immediateFailedCheckedFuture(ex);
+        when(writeTx.read(LogicalDatastoreType.OPERATIONAL, id)).thenReturn(futureData);
+        assertSame(ctx.read(id).get(), data);
+    }
+
+    @Test
+    public void testMerge() throws Exception {
+        ctx.merge(id, data);
+        verify(writeTx).merge(LogicalDatastoreType.OPERATIONAL, id, data, true);
+    }
+
+    @Test
+    public void testPut() throws Exception {
+        ctx.put(id, data);
+        verify(writeTx).put(LogicalDatastoreType.OPERATIONAL, id, data, true);
+    }
+
+    @Test
+    public void testDelete() throws Exception {
+        ctx.delete(id);
+        verify(writeTx).delete(LogicalDatastoreType.OPERATIONAL, id);
+    }
+
+    @Test
+    public void testClose() throws Exception {
+        ctx.close();
+        verify(writeTx).cancel();
+    }
+
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/BindingBrokerReaderTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/BindingBrokerReaderTest.java
new file mode 100644
index 000000000..b6af72125
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/BindingBrokerReaderTest.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.read;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Optional;
+import com.google.common.util.concurrent.Futures;
+import io.fd.honeycomb.translate.read.ReadContext;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.controller.md.sal.binding.api.DataBroker;
+import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
+import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class BindingBrokerReaderTest {
+
+    @Mock
+    private DataBroker broker;
+    private InstanceIdentifier<DataObject> id = InstanceIdentifier.create(DataObject.class);
+    @Mock
+    private ReadContext ctx;
+    @Mock
+    private ReadOnlyTransaction tx;
+    @Mock
+    private DataObject data;
+    private BindingBrokerReader<DataObject, DataObjectBuilder> bbReader;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(broker.newReadOnlyTransaction()).thenReturn(tx);
+        when(tx.read(LogicalDatastoreType.CONFIGURATION, id)).thenReturn(Futures.immediateCheckedFuture(Optional.of(data)));
+        bbReader = new BindingBrokerReader<>(id, broker, LogicalDatastoreType.CONFIGURATION, DataObjectBuilder.class);
+    }
+
+    @Test
+    public void testRead() throws Exception {
+        assertEquals(id, bbReader.getManagedDataObjectType());
+        assertNotNull(bbReader.getBuilder(id));
+
+        final Optional<? extends DataObject> read = bbReader.read(id, ctx);
+        assertSame(data, read.get());
+        verify(broker).newReadOnlyTransaction();
+    }
+
+    @Test(expected = io.fd.honeycomb.translate.read.ReadFailedException.class)
+    public void testFailedRead() throws Exception {
+        when(tx.read(LogicalDatastoreType.CONFIGURATION, id))
+                .thenReturn(Futures.immediateFailedCheckedFuture(new ReadFailedException("failing")));
+        bbReader.read(id, ctx);
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void testReadCurrentAttrs() throws Exception {
+        bbReader.readCurrentAttributes(id, new DataObjectBuilder(), ctx);
+    }
+
+    static final class DataObjectBuilder implements Builder<DataObject> {
+
+        @Override
+        public DataObject build() {
+            return mock(DataObject.class);
+        }
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapperTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapperTest.java
new file mode 100644
index 000000000..ca2872139
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/KeepaliveReaderWrapperTest.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.read;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import io.fd.honeycomb.translate.read.ReadContext;
+import io.fd.honeycomb.translate.read.Reader;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class KeepaliveReaderWrapperTest {
+
+    @Mock
+    private ReadContext ctx;
+    @Mock
+    private Reader<DataObject, Builder<DataObject>> delegate;
+    @Mock
+    private Builder<DataObject> builder;
+
+    private InstanceIdentifier<DataObject> id = InstanceIdentifier.create(DataObject.class);
+    private ScheduledExecutorService exec;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        exec = Executors.newScheduledThreadPool(1);
+        when(delegate.read(any(InstanceIdentifier.class), any(ReadContext.class))).thenThrow(TestingException.class);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        exec.shutdownNow();
+    }
+
+    @Test(timeout = 10000)
+    public void testKeepalive() throws Exception {
+        final CapturingFailListener listener = new CapturingFailListener();
+
+        final KeepaliveReaderWrapper<DataObject, Builder<DataObject>> keepaliveWrapper =
+                new KeepaliveReaderWrapper<>(delegate, exec, TestingException.class, 1, listener);
+
+        keepaliveWrapper.readCurrentAttributes(id, builder, ctx);
+        verify(delegate).readCurrentAttributes(id, builder, ctx);
+
+        keepaliveWrapper.getBuilder(id);
+        verify(delegate).getBuilder(id);
+
+
+        assertTrue(listener.getTriggerFuture().get());
+        verify(delegate).read(any(InstanceIdentifier.class), any(ReadContext.class));
+
+        keepaliveWrapper.close();
+    }
+
+    @Test(timeout = 10000)
+    public void testKeepaliveCancel() throws Exception {
+        final CapturingFailListener listener = new CapturingFailListener();
+
+        final KeepaliveReaderWrapper<DataObject, Builder<DataObject>> keepaliveWrapper =
+                new KeepaliveReaderWrapper<>(delegate, exec, TestingException.class, 100000, listener);
+        keepaliveWrapper.close();
+        assertFalse(listener.getTriggerFuture().isDone());
+    }
+
+    private static final class TestingException extends RuntimeException {}
+
+    private static class CapturingFailListener implements KeepaliveReaderWrapper.KeepaliveFailureListener {
+        private CompletableFuture<Boolean> booleanCompletableFuture = new CompletableFuture<>();
+
+        @Override
+        public synchronized void onKeepaliveFailure() {
+            booleanCompletableFuture.complete(true);
+        }
+
+        synchronized Future<Boolean> getTriggerFuture() {
+            return booleanCompletableFuture;
+        }
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/ReflexiveReaderCustomizerTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/ReflexiveReaderCustomizerTest.java
new file mode 100644
index 000000000..7fb67be6e
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/ReflexiveReaderCustomizerTest.java
@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.read;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
+import com.google.common.collect.Lists;
+import io.fd.honeycomb.translate.read.ReadContext;
+import io.fd.honeycomb.translate.read.ReadFailedException;
+import java.util.Collections;
+import java.util.List;
+import javax.annotation.Nonnull;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.Augmentation;
+import org.opendaylight.yangtools.yang.binding.DataContainer;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.Identifiable;
+import org.opendaylight.yangtools.yang.binding.Identifier;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class ReflexiveReaderCustomizerTest {
+
+    @Mock
+    private ReadContext ctx;
+    private InstanceIdentifier<TestingDataObject> id = InstanceIdentifier.create(TestingDataObject.class);
+
+    @Test
+    public void testReflexCustomizer() throws Exception {
+        final ReflexiveReaderCustomizer<TestingDataObject, TestingBuilder> reflexReaderCustomizer =
+                new ReflexiveReaderCustomizer<>(TestingDataObject.class, TestingBuilder.class);
+
+        assertEquals(TestingDataObject.class, reflexReaderCustomizer.getTypeClass());
+        assertEquals(TestingBuilder.class, reflexReaderCustomizer.getBuilderClass());
+
+        assertNotNull(reflexReaderCustomizer.getBuilder(id));
+
+        // NOOP
+        final TestingBuilder builder = spy(new TestingBuilder());
+        reflexReaderCustomizer.readCurrentAttributes(id, builder, ctx);
+        verifyZeroInteractions(builder);
+
+        final TestingBuilderParent parentBuilder = new TestingBuilderParent();
+        final TestingDataObject readValue = new TestingDataObject();
+        reflexReaderCustomizer.merge(parentBuilder, readValue);
+        assertEquals(readValue, parentBuilder.getTestingDataObject());
+    }
+
+    @Test
+    public void testReflexCustomizerAugment() throws Exception {
+        final ReflexiveReaderCustomizer<TestingAugmentation, TestingAugmentBuilder> reflexReaderCustomizer =
+                new ReflexiveReaderCustomizer<>(TestingAugmentation.class, TestingAugmentBuilder.class);
+
+        final TestingBuilderParent parentBuilder = new TestingBuilderParent();
+        final TestingAugmentation readValue = new TestingAugmentation();
+        reflexReaderCustomizer.merge(parentBuilder, readValue);
+        assertEquals(readValue, parentBuilder.getAugmentation());
+    }
+
+    @Test
+    public void testReflexCustomizerList() throws Exception {
+        final ReflexiveListReaderCustomizer<TestingListObject, TestingListObject.TestingListKey, TestingListBuilder>
+                reflexReaderCustomizer =
+                new ReflexiveListReaderCustomizer<TestingListObject, TestingListObject.TestingListKey, TestingListBuilder>
+                        (TestingListObject.class, TestingListBuilder.class) {
+
+                    @Nonnull
+                    @Override
+                    public List<TestingListObject.TestingListKey> getAllIds(
+                            @Nonnull final InstanceIdentifier<TestingListObject> id,
+                            @Nonnull final ReadContext context) throws ReadFailedException {
+                        return Lists.newArrayList();
+                    }
+                };
+
+        final TestingBuilderParent parentBuilder = new TestingBuilderParent();
+        final List<TestingListObject> readValue = Lists.newArrayList(new TestingListObject(), new TestingListObject());
+        reflexReaderCustomizer.merge(parentBuilder, readValue);
+        assertEquals(readValue, parentBuilder.getTestingListObject());
+
+        final TestingListObject single = new TestingListObject();
+        reflexReaderCustomizer.merge(parentBuilder, single);
+        assertEquals(Collections.singletonList(single), parentBuilder.getTestingListObject());
+    }
+
+    static class TestingDataObject implements DataObject {
+
+        @Override
+        public Class<? extends DataContainer> getImplementedInterface() {
+            return DataObject.class;
+        }
+    }
+
+    static class TestingAugmentation implements DataObject, Augmentation<DataObject> {
+
+        @Override
+        public Class<? extends DataContainer> getImplementedInterface() {
+            return DataObject.class;
+        }
+    }
+
+    static class TestingListObject implements DataObject, Identifiable<TestingListObject.TestingListKey> {
+
+        @Override
+        public Class<? extends DataContainer> getImplementedInterface() {
+            return DataObject.class;
+        }
+
+        @Override
+        public TestingListKey getKey() {
+            return new TestingListKey();
+        }
+
+        static class TestingListKey implements Identifier<TestingListObject> {
+        }
+    }
+
+
+    static class TestingBuilder implements Builder<TestingDataObject> {
+
+        @Override
+        public TestingDataObject build() {
+            return new TestingDataObject();
+        }
+    }
+
+    static class TestingAugmentBuilder implements Builder<TestingAugmentation> {
+
+        @Override
+        public TestingAugmentation build() {
+            return new TestingAugmentation();
+        }
+    }
+
+    static class TestingListBuilder implements Builder<TestingListObject> {
+
+        @Override
+        public TestingListObject build() {
+            return new TestingListObject();
+        }
+    }
+
+    static class TestingBuilderParent implements Builder<DataObject> {
+
+        private TestingDataObject object;
+        private Augmentation<DataObject> augmentation;
+        private List<TestingListObject> listObjects;
+
+        public TestingBuilderParent setTestingDataObject(@Nonnull final TestingDataObject object) {
+            this.object = object;
+            return this;
+        }
+
+        public TestingDataObject getTestingDataObject() {
+            return object;
+        }
+
+        public TestingBuilderParent setTestingListObject(@Nonnull final List<TestingListObject> listObjects) {
+            this.listObjects = listObjects;
+            return this;
+        }
+
+        public List<TestingListObject> getTestingListObject() {
+            return listObjects;
+        }
+
+        public TestingBuilderParent addAugmentation(Class<? extends Augmentation<DataObject>> augmentationType,
+                                                    Augmentation<DataObject> augmentation) {
+            this.augmentation = augmentation;
+            return this;
+        }
+
+        public Augmentation<DataObject> getAugmentation() {
+            return augmentation;
+        }
+
+        @Override
+        public TestingDataObject build() {
+            return new TestingDataObject();
+        }
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderRegistryTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderRegistryTest.java
new file mode 100644
index 000000000..06cb8498f
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderRegistryTest.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.read.registry;
+
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject3;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject3.DataObject31;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject4;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject4.DataObject41;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import io.fd.honeycomb.translate.read.ReadContext;
+import io.fd.honeycomb.translate.read.Reader;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class CompositeReaderRegistryTest {
+
+    @Mock
+    private ReadContext ctx;
+    private CompositeReaderRegistry reg;
+    private Reader<DataObject31, Builder<DataObject31>> reader31;
+    private Reader<DataObject3, Builder<DataObject3>> rootReader3;
+    private Reader<DataObject41, Builder<DataObject41>> reader41;
+    private Reader<DataObject4, Builder<DataObject4>> rootReader4;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        reader31 = mockReader(DataObject31.class);
+        rootReader3 =
+                spy(CompositeReader.createForReader(
+                        mockReader(DataObject3.class),
+                        ImmutableMap.of(DataObject31.class, reader31)));
+
+        reader41 = mockReader(DataObject41.class);
+        rootReader4 =
+                spy(CompositeReader.createForReader(
+                        mockReader(DataObject4.class), ImmutableMap.of(
+                                DataObject41.class, reader41)));
+
+        reg = new CompositeReaderRegistry(Lists.newArrayList(rootReader3, rootReader4));
+    }
+
+    @Test
+    public void testReadAll() throws Exception {
+        reg.readAll(ctx);
+
+        // Invoked according to composite ordering
+        final InOrder inOrder = inOrder(rootReader3, rootReader4, reader31, reader41);
+        inOrder.verify(rootReader3).read(any(InstanceIdentifier.class), any(ReadContext.class));
+        inOrder.verify(reader31).read(any(InstanceIdentifier.class), any(ReadContext.class));
+        inOrder.verify(rootReader4).read(any(InstanceIdentifier.class), any(ReadContext.class));
+        inOrder.verify(reader41).read(any(InstanceIdentifier.class), any(ReadContext.class));
+    }
+
+    @Test
+    public void testReadSingleRoot() throws Exception {
+        reg.read(DataObject3.IID, ctx);
+
+        // Invoked according to composite ordering
+        final InOrder inOrder = inOrder(rootReader3, rootReader4, reader31, reader41);
+        inOrder.verify(rootReader3).read(any(InstanceIdentifier.class), any(ReadContext.class));
+        inOrder.verify(reader31).read(any(InstanceIdentifier.class), any(ReadContext.class));
+
+        // Only subtree under DataObject3 should be read
+        verify(rootReader4, times(0)).read(any(InstanceIdentifier.class), any(ReadContext.class));
+        verify(reader41, times(0)).read(any(InstanceIdentifier.class), any(ReadContext.class));
+    }
+
+    @SuppressWarnings("unchecked")
+    static <D extends DataObject, B extends Builder<D>> Reader<D, B> mockReader(final Class<D> dataType)
+            throws Exception {
+        final Reader r = mock(Reader.class);
+        final Object iid = dataType.getDeclaredField("IID").get(null);
+        when(r.getManagedDataObjectType()).thenReturn((InstanceIdentifier) iid);
+        final Builder builder = mock(Builder.class);
+        when(builder.build()).thenReturn(mock(dataType));
+        when(r.getBuilder(any(InstanceIdentifier.class))).thenReturn(builder);
+        when(r.read(any(InstanceIdentifier.class), any(ReadContext.class))).thenReturn(Optional.of(mock(dataType)));
+        return (Reader<D, B>) r;
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderTest.java
new file mode 100644
index 000000000..9ae036013
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/read/registry/CompositeReaderTest.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.read.registry;
+
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject4;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObject4.DataObject41;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObjectK;
+import static io.fd.honeycomb.translate.util.DataObjects.DataObjectKey;
+import static io.fd.honeycomb.translate.util.read.registry.CompositeReaderRegistryTest.mockReader;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import io.fd.honeycomb.translate.read.ListReader;
+import io.fd.honeycomb.translate.read.ReadContext;
+import io.fd.honeycomb.translate.read.Reader;
+import io.fd.honeycomb.translate.util.DataObjects;
+import java.util.List;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.yangtools.concepts.Builder;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.Identifiable;
+import org.opendaylight.yangtools.yang.binding.Identifier;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class CompositeReaderTest {
+
+    @Mock
+    private ReadContext ctx;
+    private Reader<DataObject41, Builder<DataObject41>> reader41;
+    private Reader<DataObject4, Builder<DataObject4>> reader4;
+    private Reader<DataObject4, Builder<DataObject4>> compositeReader;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        reader41 = mockReader(DataObject41.class);
+        reader4 = mockReader(DataObject4.class);
+        compositeReader = CompositeReader
+                .createForReader(reader4, ImmutableMap.of(DataObject41.class, reader41));
+    }
+
+    @Test
+    public void testReadCurrent() throws Exception {
+        compositeReader.read(DataObject4.IID, ctx);
+        verify(reader4).readCurrentAttributes(eq(DataObject4.IID), any(Builder.class), eq(ctx));
+        verify(reader41).read(DataObject41.IID, ctx);
+    }
+
+    @Test
+    public void testReadJustChild() throws Exception {
+        // Delegating read to child
+        compositeReader.read(DataObject41.IID, ctx);
+        verify(reader4, times(0))
+                .readCurrentAttributes(any(InstanceIdentifier.class), any(Builder.class), any(ReadContext.class));
+        verify(reader41).read(DataObject41.IID, ctx);
+    }
+
+    @Test
+    public void testReadFallback() throws Exception {
+        // Delegating read to delegate as a fallback since IID does not fit, could be handled by the delegate if its
+        // a subtree handler
+        compositeReader.read(DataObjects.DataObject4.DataObject42.IID, ctx);
+        verify(reader4).read(DataObjects.DataObject4.DataObject42.IID, ctx);
+        verify(reader41, times(0)).read(any(InstanceIdentifier.class), any(ReadContext.class));
+    }
+
+    @Test
+    public void testList() throws Exception {
+        final Reader<DataObjectK.DataObjectK1, Builder<DataObjectK.DataObjectK1>> readerK1 =
+                mockReader(DataObjectK.DataObjectK1.class);
+        final ListReader<DataObjectK, DataObjectKey, Builder<DataObjectK>> readerK =
+                mockListReader(DataObjectK.class, Lists.newArrayList(new DataObjectKey(), new DataObjectKey()));
+        final ListReader<DataObjectK, DataObjectKey, Builder<DataObjectK>>
+                compositeReaderK = (ListReader<DataObjectK, DataObjectKey, Builder<DataObjectK>>)
+                CompositeReader.createForReader(readerK, ImmutableMap.of(DataObject41.class, readerK1));
+
+        compositeReaderK.readList(DataObjectK.IID, ctx);
+
+        verify(readerK).getAllIds(DataObjectK.IID, ctx);
+        verify(readerK, times(2))
+                .readCurrentAttributes(any(InstanceIdentifier.class), any(Builder.class), any(ReadContext.class));
+    }
+
+    @SuppressWarnings("unchecked")
+    static <D extends DataObject & Identifiable<K>, K extends Identifier<D>, B extends Builder<D>> ListReader<D, K, B> mockListReader(
+            final Class<D> dataType, List<K> keys)
+            throws Exception {
+        final ListReader r = mock(ListReader.class);
+        final Object iid = dataType.getDeclaredField("IID").get(null);
+        when(r.getManagedDataObjectType()).thenReturn((InstanceIdentifier) iid);
+        final Builder builder = mock(Builder.class);
+        when(builder.build()).thenReturn(mock(dataType));
+        when(r.getBuilder(any(InstanceIdentifier.class))).thenReturn(builder);
+        when(r.read(any(InstanceIdentifier.class), any(ReadContext.class))).thenReturn(Optional.of(mock(dataType)));
+        when(r.getAllIds(any(InstanceIdentifier.class), any(ReadContext.class))).thenReturn(keys);
+        return (ListReader<D, K, B>) r;
+    }
+
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/AbstractGenericWriterTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/AbstractGenericWriterTest.java
new file mode 100644
index 000000000..14c9c6044
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/AbstractGenericWriterTest.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.write;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import io.fd.honeycomb.translate.write.WriteContext;
+import io.fd.honeycomb.translate.write.WriteFailedException;
+import javax.annotation.Nonnull;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class AbstractGenericWriterTest {
+
+    private InstanceIdentifier<DataObject> id = InstanceIdentifier.create(DataObject.class);
+    @Mock
+    private DataObject before;
+    @Mock
+    private DataObject after;
+    @Mock
+    private WriteContext ctx;
+    private TestingWriter t;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        t = spy(new TestingWriter());
+    }
+
+    @Test
+    public void testDelete() throws Exception {
+        before = mock(DataObject.class);
+        t.update(id, before, null, ctx);
+
+        verify(t).deleteCurrentAttributes(id, before, ctx);
+    }
+
+    @Test
+    public void testUpdate() throws Exception {
+        before = mock(DataObject.class);
+        t.update(id, before, after, ctx);
+
+        verify(t).updateCurrentAttributes(id, before, after, ctx);
+    }
+
+    @Test
+    public void testNoUpdate() throws Exception {
+        before = mock(DataObject.class);
+        t.update(id, before, before, ctx);
+
+        verify(t, times(0)).updateCurrentAttributes(id, before, after, ctx);
+    }
+
+    @Test
+    public void testCreate() throws Exception {
+        before = mock(DataObject.class);
+        t.update(id, null, after, ctx);
+
+        verify(t).writeCurrentAttributes(id, after, ctx);
+    }
+
+    private static class TestingWriter extends AbstractGenericWriter<DataObject> {
+
+        TestingWriter() {
+            super(InstanceIdentifier.create(DataObject.class));
+        }
+
+        @Override
+        protected void writeCurrentAttributes(@Nonnull final InstanceIdentifier<DataObject> id,
+                                              @Nonnull final DataObject data, @Nonnull final WriteContext ctx)
+                throws WriteFailedException {
+
+        }
+
+        @Override
+        protected void deleteCurrentAttributes(@Nonnull final InstanceIdentifier<DataObject> id,
+                                               @Nonnull final DataObject dataBefore, @Nonnull final WriteContext ctx)
+                throws WriteFailedException {
+
+        }
+
+        @Override
+        protected void updateCurrentAttributes(@Nonnull final InstanceIdentifier<DataObject> id,
+                                               @Nonnull final DataObject dataBefore,
+                                               @Nonnull final DataObject dataAfter,
+                                               @Nonnull final WriteContext ctx) throws WriteFailedException {
+
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/NoopWriterRegistryTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/NoopWriterRegistryTest.java
new file mode 100644
index 000000000..411f24bc3
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/NoopWriterRegistryTest.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.translate.util.write;
+
+import org.junit.Test;
+
+public class NoopWriterRegistryTest {
+
+    @Test
+    public void testNoop() throws Exception {
+        final NoopWriterRegistry noopWriterRegistry = new NoopWriterRegistry();
+        noopWriterRegistry.update(null, null);
+        noopWriterRegistry.close();
+    }
+}
\ No newline at end of file
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/registry/FlatWriterRegistryBuilderTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/registry/FlatWriterRegistryBuilderTest.java
index 79590a5a0..4f7ab2894 100644
--- a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/registry/FlatWriterRegistryBuilderTest.java
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/write/registry/FlatWriterRegistryBuilderTest.java
@@ -7,15 +7,22 @@ import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
+import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
+import com.google.common.collect.Multimaps;
 import com.google.common.collect.Sets;
 import io.fd.honeycomb.translate.util.DataObjects;
+import io.fd.honeycomb.translate.write.DataObjectUpdate;
+import io.fd.honeycomb.translate.write.WriteContext;
 import io.fd.honeycomb.translate.write.Writer;
+import io.fd.honeycomb.translate.write.registry.WriterRegistry;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import org.junit.Test;
 import org.opendaylight.yangtools.yang.binding.DataObject;
@@ -23,7 +30,6 @@ import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 public class FlatWriterRegistryBuilderTest {
 
-
     @Test
     public void testRelationsBefore() throws Exception {
         final FlatWriterRegistryBuilder flatWriterRegistryBuilder = new FlatWriterRegistryBuilder();
@@ -47,6 +53,38 @@ public class FlatWriterRegistryBuilderTest {
     }
 
     @Test
+    public void testBuild() throws Exception {
+        final FlatWriterRegistryBuilder flatWriterRegistryBuilder = new FlatWriterRegistryBuilder();
+        final Writer<? extends DataObject> writer = mockWriter(DataObjects.DataObject3.class);
+        flatWriterRegistryBuilder.add(writer);
+        final WriterRegistry build = flatWriterRegistryBuilder.build();
+        final InstanceIdentifier<DataObjects.DataObject3> id = InstanceIdentifier.create(DataObjects.DataObject3.class);
+        final DataObjectUpdate update = mock(DataObjectUpdate.class);
+        WriterRegistry.DataObjectUpdates updates = new WriterRegistry.DataObjectUpdates(
+                Multimaps.forMap(Collections.singletonMap(id, update)),
+                Multimaps.forMap(Collections.emptyMap()));
+        build.update(updates, mock(WriteContext.class));
+
+        verify(writer)
+                .update(any(InstanceIdentifier.class), any(DataObject.class), any(DataObject.class), any(WriteContext.class));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testBuildUnknownWriter() throws Exception {
+        final FlatWriterRegistryBuilder flatWriterRegistryBuilder = new FlatWriterRegistryBuilder();
+        final Writer<? extends DataObject> writer = mockWriter(DataObjects.DataObject3.class);
+        flatWriterRegistryBuilder.add(writer);
+        final WriterRegistry build = flatWriterRegistryBuilder.build();
+
+        final InstanceIdentifier<DataObjects.DataObject1> id2 = InstanceIdentifier.create(DataObjects.DataObject1.class);
+        final DataObjectUpdate update2 = mock(DataObjectUpdate.class);
+        final WriterRegistry.DataObjectUpdates updates = new WriterRegistry.DataObjectUpdates(
+                Multimaps.forMap(Collections.singletonMap(id2, update2)),
+                Multimaps.forMap(Collections.emptyMap()));
+        build.update(updates, mock(WriteContext.class));
+    }
+
+    @Test
     public void testRelationsAfter() throws Exception {
         final FlatWriterRegistryBuilder flatWriterRegistryBuilder = new FlatWriterRegistryBuilder();
         /*
@@ -56,7 +94,8 @@ public class FlatWriterRegistryBuilderTest {
         flatWriterRegistryBuilder.add(mockWriter(DataObjects.DataObject1.class));
         flatWriterRegistryBuilder.addAfter(mockWriter(DataObjects.DataObject2.class), DataObjects.DataObject1.IID);
         flatWriterRegistryBuilder.addAfter(mockWriter(DataObjects.DataObject3.class), DataObjects.DataObject2.IID);
-        flatWriterRegistryBuilder.addAfter(mockWriter(DataObjects.DataObject4.class), DataObjects.DataObject2.IID);
+        flatWriterRegistryBuilder.addAfter(mockWriter(DataObjects.DataObject4.class),
+                Lists.newArrayList(DataObjects.DataObject2.IID, DataObjects.DataObject3.IID));
         final ImmutableMap<InstanceIdentifier<?>, Writer<?>> mappedWriters =
                 flatWriterRegistryBuilder.getMappedHandlers();