     }
     
     let attrs = entity.attributes
-    XCTAssertEqual(attrs.count, 14)
+    XCTAssertEqual(attrs.count, 14,
+                   "attribute counts do not match: \(attrs)")
     
     let pkeys = entity.primaryKeyAttributeNames
     XCTAssertNotNil(pkeys)

      return
    }
    addressEntity.dump()
    XCTAssertEqual(addressEntity.attributes.count, 2)
    
    let pkeys = addressEntity.primaryKeyAttributeNames
    XCTAssertNotNil(pkeys)

    model.dump()

    let attrs = entity.attributes
    XCTAssertEqual(attrs.count, 4,
                   "attribute counts do not match: \(attrs)")
    
    if let attr = entity[attribute: "isPerson"] {
      XCTAssertEqual(attr.name,       "isPerson")
