### Question:
GraphEntityMutation implements Entity.Mutation { @Override public Mutation deleteAttribute(Name name) { attributeOperatons.unsetAttributeValue( Preconditions.argumentNotNull(name,"name")); return this; } GraphEntityMutation(Entity entity,
            OperationPipeline assemblyLine,
            BatchMutation batchMutation); @Override ValueSpecifier<Mutation> withAttribute(Name name); @Override Mutation deleteAttribute(Name name); @Override Mutation deleteAttributes(Attribute.Family namespace); @Override Mutation delete(); @Override com.intuit.ugc.api.BatchMutation ready();  }### Answer:
@Test public void testDeleteAttributeWithNullAttribute() { GraphEntityMutation graphEntityMutation = createGraphEntityMutation(null); try{ graphEntityMutation.deleteAttribute(null); fail("Should throw exception if called with null attribute"); }catch(Exception e){ assertTrue(e instanceof IllegalArgumentException); } }
@Test public void testDeleteAttributeWithValidAttributeName(){ GraphEntityMutation graphEntityMutation = createGraphEntityMutation(null); Mutation deleteAttribute = graphEntityMutation .deleteAttribute(TartanImplTestConstants.ATTR_DUMMY_ATTRIBUTE_NAME); assertNotNull(deleteAttribute); }