Creating Web API in ASP.NET Core 2.0 - Part 2 - Unit Tests

Step 07 - Add Unit Tests

In order to add unit tests for API project, follow these steps:

Right click on Solution > Add > New Project

Go to Installed > Visual C# > Test > xUnit Test Project (.NET Core)

Set the name for project as Sample.API.UnitTests

Click OK

Manage references for Sample.API.UnitTests project:

Now add a reference for Sample.API project:

Once we have created the project, add the following NuGet packages for project:

Microsoft.AspNetCore.Mvc.Core

Microsoft.EntityFrameworkCore.InMemory

Remove UnitTest1.cs file.

Save changes and build Sample.API.UnitTests project.

Now we proceed to add code related for unit tests, these tests will work with In memory database.

What is TDD? Testing is a common practice in nowadays, because with unit tests, it's easy to performing tests for features before to publish, Test Driven Development (TDD) is the way to define unit tests and validate the behavior in code.

Another concept in TDD is AAA: Arrange, Act and Assert; Arrange is the block for creation of objects, Act is the block to place all invocations for methods and Assert is the block to validate the results from methods invocation.

Since We're working with In memory database for unit tests, We need to create a class to mock SampleDbContext class and also add data to perform testing for SampleDbContext extension methods.

To be clear: these unit tests do not establish a connection with SQL Server.

For unit tests, add the following files:

1. DbContextExtensions.cs
2. DbContextMocker.cs
3. StoragehouseControllerUnitTest.cs

Code for DbContextExtensions.cs file:

using System;

using Sample.API.Models;

 namespace Sample.API.UnitTests

{

    public static class DbContextExtensions

    {

        public static void Seed(this SampleDbContext dbContext)

        {

            // Add entities for DbContext instance

             dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 1,

                StockItemName = "USB missile launcher (Green)",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 25.00m,

                RecommendedRetailPrice = 37.38m,

                TypicalWeightPerUnit = 0.300m,

                MarketingComments = "Complete with 12 projectiles",

                CustomFields = "{ \"CountryOfManufacture\": \"China\", \"Tags\": [\"USB Powered\"] }",

                Tags = "[\"USB Powered\"]",

                SearchDetails = "USB missile launcher (Green) Complete with 12 projectiles",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 2,

                StockItemName = "USB rocket launcher (Gray)",

                SupplierID = 12,

                ColorID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 25.00m,

                RecommendedRetailPrice = 37.38m,

                TypicalWeightPerUnit = 0.300m,

                MarketingComments = "Complete with 12 projectiles",

                CustomFields = "{ \"CountryOfManufacture\": \"China\", \"Tags\": [\"USB Powered\"] }",

                Tags = "[\"USB Powered\"]",

                SearchDetails = "USB rocket launcher (Gray) Complete with 12 projectiles",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 3,

                StockItemName = "Office cube periscope (Black)",

                SupplierID = 12,

                ColorID = 3,

                UnitPackageID = 7,

                OuterPackageID = 6,

                LeadTimeDays = 14,

                QuantityPerOuter = 10,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 18.50m,

                RecommendedRetailPrice = 27.66m,

                TypicalWeightPerUnit = 0.250m,

                MarketingComments = "Need to see over your cubicle wall? This is just what's needed.",

                CustomFields = "{ \"CountryOfManufacture\": \"China\", \"Tags\": [] }",

                Tags = "[]",

                SearchDetails = "Office cube periscope (Black) Need to see over your cubicle wall? This is just what's needed.",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:00:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 4,

                StockItemName = "USB food flash drive - sushi roll",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - sushi roll ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 5,

                StockItemName = "USB food flash drive - hamburger",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"16GB\",\"USB Powered\"] }",

                Tags = "[\"16GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - hamburger ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 6,

                StockItemName = "USB food flash drive - hot dog",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - hot dog ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 7,

                StockItemName = "USB food flash drive - pizza slice",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"16GB\",\"USB Powered\"] }",

                Tags = "[\"16GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - pizza slice ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 8,

                StockItemName = "USB food flash drive - dim sum 10 drive variety pack",

                SupplierID = 12,

                UnitPackageID = 9,

                OuterPackageID = 9,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 240.00m,

                RecommendedRetailPrice = 358.80m,

                TypicalWeightPerUnit = 0.500m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - dim sum 10 drive variety pack ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 9,

                StockItemName = "USB food flash drive - banana",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"16GB\",\"USB Powered\"] }",

                Tags = "[\"16GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - banana ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 10,

                StockItemName = "USB food flash drive - chocolate bar",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - chocolate bar ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 11,

                StockItemName = "USB food flash drive - cookie",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"16GB\",\"USB Powered\"] }",

                Tags = "[\"16GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - cookie ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            });

 

            dbContext.StockItems.Add(new StockItem

            {

                StockItemID = 12,

                StockItemName = "USB food flash drive - donut",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB food flash drive - donut ",

                LastEditedBy = 1,

                ValidFrom = Convert.ToDateTime("5/31/2016 11:11:00 PM"),

                ValidTo = Convert.ToDateTime("12/31/9999 11:59:59 PM")

            }); 

            dbContext.SaveChanges();

        }

    }

}

Code for DbContextMocker.cs file:

using Microsoft.EntityFrameworkCore;

using Sample.API.Models;

 namespace Sample.API.UnitTests

{

    public static class DbContextMocker

    {

        public static SampleDbContext GetSampleDbContext(string dbName)

        {

            // Create options for DbContext instance

            var options = new DbContextOptionsBuilder<SampleDbContext>()

                .UseInMemoryDatabase(databaseName: dbName)

                .Options;

             // Create instance of DbContext

            var dbContext = new SampleDbContext(options);

             // Add entities in memory

            dbContext.Seed();

             return dbContext;

        }

    }

}

Code for StoragehouseControllerUnitTest.cs file:

using System;

using System.Threading.Tasks;

using Microsoft.AspNetCore.Mvc;

using Sample.API.Controllers;

using Sample.API.Models;

using Xunit;

 namespace Sample.API.UnitTests

{

    public class StoragehouseControllerUnitTest

    {

        [Fact]

        public async Task TestGetStockItemsAsync()

        {

            // Arrange

            var dbContext = DbContextMocker.GetSampleDbContext(nameof(TestGetStockItemsAsync));

            var controller = new StoragehouseController(null, dbContext);

             // Act

            var response = await controller.GetStockItemsAsync() as ObjectResult;

            var value = response.Value as IPagedResponse<StockItem>;

             dbContext.Dispose();

             // Assert

            Assert.False(value.DidError);

        }

 

        [Fact]

        public async Task TestGetStockItemAsync()

        {

            // Arrange

            var dbContext = DbContextMocker.GetSampleDbContext(nameof(TestGetStockItemAsync));

            var controller = new StoragehouseController(null, dbContext);

            var id = 1;

             // Act

            var response = await controller.GetStockItemAsync(id) as ObjectResult;

            var value = response.Value as ISingleResponse<StockItem>;

             dbContext.Dispose();

             // Assert

            Assert.False(value.DidError);

        }

 

        [Fact]

        public async Task TestPostStockItemAsync()

        {

            // Arrange

            var dbContext = DbContextMocker.GetSampleDbContext(nameof(TestPostStockItemAsync));

            var controller = new StoragehouseController(null, dbContext);

            var request = new PostStockItemsRequest

            {

                StockItemID = 100,

                StockItemName = "USB anime flash drive - Goku",

                SupplierID = 12,

                UnitPackageID = 7,

                OuterPackageID = 7,

                LeadTimeDays = 14,

                QuantityPerOuter = 1,

                IsChillerStock = false,

                TaxRate = 15.000m,

                UnitPrice = 32.00m,

                RecommendedRetailPrice = 47.84m,

                TypicalWeightPerUnit = 0.050m,

                CustomFields = "{ \"CountryOfManufacture\": \"Japan\", \"Tags\": [\"32GB\",\"USB Powered\"] }",

                Tags = "[\"32GB\",\"USB Powered\"]",

                SearchDetails = "USB anime flash drive - Goku",

                LastEditedBy = 1,

                ValidFrom = DateTime.Now,

                ValidTo = DateTime.Now.AddYears(5)

            };

             // Act

            var response = await controller.PostStockItemAsync(request) as ObjectResult;

            var value = response.Value as ISingleResponse<StockItem>;

             dbContext.Dispose();

             // Assert

            Assert.False(value.DidError);

        }

        [Fact]

        public async Task TestPutStockItemAsync()

        {

            // Arrange

            var dbContext = DbContextMocker.GetSampleDbContext(nameof(TestPutStockItemAsync));

            var controller = new StoragehouseController(null, dbContext);

            var id = 12;

            var request = new PutStockItemsRequest

            {

                StockItemName = "USB food flash drive (Update)",

                SupplierID = 12,

                ColorID = 3

            };

             // Act

            var response = await controller.PutStockItemAsync(id, request) as ObjectResult;

            var value = response.Value as IResponse;

             dbContext.Dispose();

             // Assert

            Assert.False(value.DidError);

        }

         [Fact]

        public async Task TestDeleteStockItemAsync()

        {

            // Arrange

            var dbContext = DbContextMocker.GetSampleDbContext(nameof(TestDeleteStockItemAsync));

            var controller = new StoragehouseController(null, dbContext);

            var id = 5;

            // Act

            var response = await controller.DeleteStockItemAsync(id) as ObjectResult;

            var value = response.Value as IResponse;

             dbContext.Dispose();

             // Assert

            Assert.False(value.DidError);

        }

    }

}

As We can see, StoragehouseControllerUnitTest contains all tests for Web API, these are the methods:

METHOD	DESCRIPTION
TestGetStockItemsAsync	Retrieves the stock items
TestGetStockItemAsync	Retrieves an existing stock item by ID
TestPostStockItemAsync	Creates a new stock item
TestPutStockItemAsync	Updates an existing stock item
TestDeleteStockItemAsync	Deletes an existing stock item

How Unit Tests Work?

DbContextMocker creates an instance of SampleDbContext using in memory database, the dbName parameter sets the name for in memory database; then there is an invocation for Seed method, this method adds entities for SampleDbContext instance in order to provide results.

DbContextExtensions class contains Seed extension method.

StoragehouseControllerUnitTest class contains all tests for StoragehouseController class.

Keep in mind each test uses a different in memory database, inside of each test method. We retrieve in memory database using the name of test method with nameof operator.

At this level (Unit tests), we only need to check the operations for repositories, there is no need to work with a SQL database (relations, transactions, etc.).

The process for unit tests is:

1. Create an instance of DbContext
2. Create an instance of controller
3. Invoke controller's method
4. Get value from controller's invocation
5. Dispose DbContext instance
6. Validate response

Running Unit Tests

Save all changes and build Sample.API.UnitTests project.

Now, check tests in test explorer:

Run all tests using test explorer, if you get any error, check the error message, review code and repeat the process.

Code Challenge

At this point, you have skills to extend API, take this as a challenge for you and add the following tests:

TEST	DESCRIPTION
Get stock items by parameters	Make a request for stock items searching by lastEditedBy, colorID, outerPackageID, supplierID, unitPackageID parameters.
Get a non existing stock item	Get a stock item using a non existing ID and check Web API returns NotFound (404) status.
Add a stock item with existing name	Add a stock item with an existing name and check Web API returns BadRequest (400) status.
Add a stock item without required fields	Add a stock item without required fields and check Web API returns BadRequest (400) status.
Update a non existing stock item	Update a stock item using a non existing ID and check Web API returns NotFound (404) status.
Update an existing stock item without required fields	Update an existing stock item without required fields and check Web API returns BadRequest (400) status.
Delete a non existing stock item	Delete a stock item using a non existing ID and check Web API returns NotFound (404) status.
Delete a stock item with orders	Delete a stock item using a non existing ID and check Web API returns NotFound (404) status.

Follow the convention used in unit and integration tests to complete this challenge.

Good luck!

Related Links

·       Unit testing C# in .NET Core using dotnet test and xUnit