feat(instance-validator): add model name to allowNull messages (#8500)

lib/instance-validator.js

@@ -322,7 +322,7 @@ class InstanceValidator {
 
     if (rawAttribute.allowNull === false && (value === null || value === undefined)) {
       const validators = this.modelInstance.validators[field];
-      const errMsg = _.get(validators, 'notNull.msg', `${field} cannot be null`);
+      const errMsg = _.get(validators, 'notNull.msg', `${this.modelInstance.constructor.name}.${field} cannot be null`);
       error = new sequelizeError.ValidationErrorItem(errMsg, 'notNull Violation', field, value);
       this.errors.push(error);
     }

test/integration/instance.validations.test.js

@@ -375,9 +375,9 @@ describe(Support.getTestDialectTeaser('InstanceValidator'), () => {
       it('correctly throws an error using create method with default generated messages', function() {
         return this.Project.create({}).catch(err => {
           expect(err).to.have.property('name', 'SequelizeValidationError');
-          expect(err.message).equal('notNull Violation: name cannot be null');
+          expect(err.message).equal('notNull Violation: Project.name cannot be null');
           expect(err.errors).to.be.an('array').and.have.length(1);
-          expect(err.errors[0]).to.have.property('message', 'name cannot be null');
+          expect(err.errors[0]).to.have.property('message', 'Project.name cannot be null');
         });
       });
     });

test/unit/instance-validator.test.js

@@ -65,6 +65,20 @@ describe(Support.getTestDialectTeaser('InstanceValidator'), () => {
 
       return expect(result).to.be.rejectedWith(SequelizeValidationError);
     });
+
+    it('has a useful default error message for not null validation failures', () => {
+      const User = Support.sequelize.define('user', {
+        name: {
+          type: Support.Sequelize.STRING,
+          allowNull: false
+        }
+      });
+
+      const instanceValidator = new InstanceValidator(User.build());
+      const result = instanceValidator.validate();
+
+      return expect(result).to.be.rejectedWith(SequelizeValidationError, /user\.name cannot be null/);
+    });
   });
 
   describe('_validateAndRunHooks', () => {