PrimeNumbers

Comparisson between Unit Tests using Specflow (BDD tool) & xUnit traditional unit testing

This repository hosts a demo intended to compare how to execute Test Driven Development following two different approaches:

Composition

This project has been built on C# (.NET 5) using Visual Studio, hence the solution file (.sln).

There is only a single project, inside folder PrimeNumbers. Users using Visual Studio Code or other IDE can start from here

• PrimeNumber.cs This is a static class with a single operation. Commented there appear the different steps given dring test development.

        static public bool IsPrime(int number)
        {
            for (int i = 2; i < number; i++)
            {
                if (number % i == 0)
                {
                    return false;
                }
            }
            return true;
        }

Gherkin Unit Tests folder

These are the Unit Tests created using Gherkin. .* PrimeNumbers.feature This is the feature file. In order to add a new

Feature: PrimeNumbers
	As a SW Developer,
	I want to have an operation
	returning whether a number is prime or not

@PrimeNumbers
Scenario Outline: Detecting a number is prime
	Given a number '<number>'
	When I check whether is prime or not
	Then the operation result shall be '<result>'
Examples: 
     | number | result |
     | 02     | true   |
     | 03     | true   |
     | 04     | false  |
     | 05     | true   |

New tests can be created by adding a single line:

  Feature: PrimeNumbers
	As a SW Developer,
	I want to have an operation
	returning whether a number is prime or not

@PrimeNumbers
Scenario Outline: Detecting a number is prime
	Given a number '<number>'
	When I check whether is prime or not
	Then the operation result shall be '<result>'
Examples: 
     | number | result |
     | 02     | true   |
     | 03     | true   |
     | 04     | false  |
     | 05     | true   |
     | 06     | false  |
     | 07     | true   |
     | 08     | false  |
     | 09     | false  |
Feature: PrimeNumbers
	As a SW Developer,
	I want to have an operation
	returning whether a number is prime or not

@PrimeNumbers
Scenario Outline: Detecting a number is prime
	Given a number '<number>'
	When I check whether is prime or not
	Then the operation result shall be '<result>'
Examples: 
     | number | result |
     | 02     | true   |
     | 03     | true   |
     | 04     | false  |
     | 05     | true   |
     | 06     | false  |

.* PrimeNumberSteps.cs These are the step file. Here we link gherkin steps with specific technology. In this case we're working on C# hence we use Specflow to support Gherkin syntax and step binding

Traditional Unit Test

.* PrimeNumberTests.cs This file hostes the same Unit Tests for TDD but created using a traditional way.

In this case, in order to build a new test, we need to add a C# block. In this example, the name of the tests is self-descriptive:

        [Fact]
        public void _08_is_not_prime()
        {
            Assert.False(PrimeNumber.IsPrime(8));
        }
        [Fact]
        public void _09_is_not_prime()
        {
            Assert.False(PrimeNumber.IsPrime(8));
        }

We can add new tests by copy&paste and modify the code

        [Fact]
        public void _08_is_not_prime()
        {
            Assert.False(PrimeNumber.IsPrime(8));
        }
        [Fact]
        public void _09_is_not_prime()
        {
            Assert.False(PrimeNumber.IsPrime(9));
        }
        [Fact]
        public void _10_is_not_prime()
        {
            Assert.False(PrimeNumber.IsPrime(10));
        }