public async Task ShouldThrowDependencyExceptionOnDeleteWhenDbUpdateConcurrencyExceptionOccursAndLogItAsync()
        {
            // given
            Guid randomExamId = Guid.NewGuid();
            Guid inputExamId  = randomExamId;
            var  databaseUpdateConcurrencyException = new DbUpdateConcurrencyException();
            var  lockedExamException = new LockedExamException(databaseUpdateConcurrencyException);

            var expectedExamDependencyException =
                new ExamDependencyException(lockedExamException);

            this.storageBrokerMock.Setup(broker =>
                                         broker.SelectExamByIdAsync(inputExamId))
            .ThrowsAsync(databaseUpdateConcurrencyException);

            // when
            ValueTask <Exam> deleteExamTask =
                this.examService.RemoveExamByIdAsync(inputExamId);

            // then
            await Assert.ThrowsAsync <ExamDependencyException>(() =>
                                                               deleteExamTask.AsTask());

            this.loggingBrokerMock.Verify(broker =>
                                          broker.LogError(It.Is(SameExceptionAs(expectedExamDependencyException))),
                                          Times.Once);

            this.storageBrokerMock.Verify(broker =>
                                          broker.SelectExamByIdAsync(inputExamId),
                                          Times.Once);

            this.dateTimeBrokerMock.VerifyNoOtherCalls();
            this.loggingBrokerMock.VerifyNoOtherCalls();
            this.storageBrokerMock.VerifyNoOtherCalls();
        }
        private async ValueTask <Exam> TryCatch(ReturningExamFunction returningExamFunction)
        {
            try
            {
                return(await returningExamFunction());
            }
            catch (NullExamException nullExamException)
            {
                throw CreateAndLogValidationException(nullExamException);
            }
            catch (InvalidExamException invalidExamInputException)
            {
                throw CreateAndLogValidationException(invalidExamInputException);
            }
            catch (NotFoundExamException nullExamException)
            {
                throw CreateAndLogValidationException(nullExamException);
            }
            catch (SqlException sqlException)
            {
                var failedExamStorageException =
                    new FailedExamStorageException(sqlException);

                throw CreateAndLogCriticalDependencyException(failedExamStorageException);
            }
            catch (DuplicateKeyException duplicateKeyException)
            {
                var alreadyExistsExamException =
                    new AlreadyExistsExamException(duplicateKeyException);

                throw CreateAndLogDependencyValidationException(alreadyExistsExamException);
            }
            catch (DbUpdateConcurrencyException dbUpdateConcurrencyException)
            {
                var lockedExamException = new LockedExamException(dbUpdateConcurrencyException);

                throw CreateAndLogDependencyValidationException(lockedExamException);
            }
            catch (DbUpdateException dbUpdateException)
            {
                var failedExamStorageException =
                    new FailedExamStorageException(dbUpdateException);

                throw CreateAndLogDependencyException(failedExamStorageException);
            }
            catch (Exception exception)
            {
                var failedExamServiceException =
                    new FailedExamServiceException(exception);

                throw CreateAndLogServiceException(failedExamServiceException);
            }
        }
        public async Task ShouldThrowDependencyValidationExceptionOnModifyIfDbUpdateConcurrencyErrorOccursAndLogItAsync()
        {
            // given
            Exam someExam = CreateRandomExam();

            var databaseUpdateConcurrencyException =
                new DbUpdateConcurrencyException();

            var lockedExamException =
                new LockedExamException(databaseUpdateConcurrencyException);

            var expectedExamDependencyValidationException =
                new ExamDependencyValidationException(lockedExamException);

            this.dateTimeBrokerMock.Setup(broker =>
                                          broker.GetCurrentDateTime())
            .Throws(databaseUpdateConcurrencyException);

            // when
            ValueTask <Exam> modifyExamTask =
                this.examService.ModifyExamAsync(someExam);

            // then
            await Assert.ThrowsAsync <ExamDependencyValidationException>(() =>
                                                                         modifyExamTask.AsTask());

            this.dateTimeBrokerMock.Verify(broker =>
                                           broker.GetCurrentDateTime(),
                                           Times.Once);

            this.loggingBrokerMock.Verify(broker =>
                                          broker.LogError(It.Is(SameExceptionAs(
                                                                    expectedExamDependencyValidationException))),
                                          Times.Once);

            this.storageBrokerMock.Verify(broker =>
                                          broker.SelectExamByIdAsync(someExam.Id),
                                          Times.Never);

            this.storageBrokerMock.Verify(broker =>
                                          broker.UpdateExamAsync(someExam),
                                          Times.Never);

            this.dateTimeBrokerMock.VerifyNoOtherCalls();
            this.loggingBrokerMock.VerifyNoOtherCalls();
            this.storageBrokerMock.VerifyNoOtherCalls();
        }
        public async Task ShouldThrowDependencyExceptionOnModifyIfDbUpdateConcurrencyExceptionOccursAndLogItAsync()
        {
            // given
            int            randomNegativeNumber = GetNegativeRandomNumber();
            DateTimeOffset randomDateTime       = GetRandomDateTime();
            Exam           randomExam           = CreateRandomExam(randomDateTime);
            Exam           someExam             = randomExam;

            someExam.CreatedDate = randomDateTime.AddMinutes(randomNegativeNumber);
            var databaseUpdateConcurrencyException = new DbUpdateConcurrencyException();
            var lockedExamException = new LockedExamException(databaseUpdateConcurrencyException);

            var expectedExamDependencyException =
                new ExamDependencyException(lockedExamException);

            this.storageBrokerMock.Setup(broker =>
                                         broker.SelectExamByIdAsync(someExam.Id))
            .ThrowsAsync(databaseUpdateConcurrencyException);

            this.dateTimeBrokerMock.Setup(broker =>
                                          broker.GetCurrentDateTime())
            .Returns(randomDateTime);

            // when
            ValueTask <Exam> modifyExamTask =
                this.examService.ModifyExamAsync(someExam);

            // then
            await Assert.ThrowsAsync <ExamDependencyException>(() =>
                                                               modifyExamTask.AsTask());

            this.dateTimeBrokerMock.Verify(broker =>
                                           broker.GetCurrentDateTime(),
                                           Times.Once);

            this.storageBrokerMock.Verify(broker =>
                                          broker.SelectExamByIdAsync(someExam.Id),
                                          Times.Once);

            this.loggingBrokerMock.Verify(broker =>
                                          broker.LogError(It.Is(SameExceptionAs(expectedExamDependencyException))),
                                          Times.Once);

            this.loggingBrokerMock.VerifyNoOtherCalls();
            this.storageBrokerMock.VerifyNoOtherCalls();
            this.dateTimeBrokerMock.VerifyNoOtherCalls();
        }