xUnit

Two packages add [ModuleTest] to xUnit v3 test projects. Use the package for the version of xunit.v3 in your test project:

xunit.v3 version	Package
3.2.2 and all subsequent versions before 4.0.0	DependencyModules.xUnit
4.0.0 and all subsequent versions before 5.0.0	DependencyModules.xUnit4

The two packages have the same types in the same namespaces. Thus, when you change from one package to the other, your tests do not change.

Install

For xunit.v3 version 3:

dotnet add package DependencyModules.xUnit

For xunit.v3 version 4:

dotnet add package DependencyModules.xUnit4

Also add references to xunit.v3 and to a test runner, for example xunit.runner.visualstudio.

With xunit.v3 version 4 and the .NET 10 SDK, dotnet test in the VSTest mode stops with an error from Microsoft.Testing.Platform. To prevent this error, use the MTP mode of dotnet test, or use xunit.v3.mtp-off in place of xunit.v3. For more information, refer to the xUnit 4.0.0 release notes.

[ModuleTest]

[ModuleTest] is in the DependencyModules.xUnit.Attributes namespace. Put it on a test method. Do not also put [Fact] or [Theory] on the method. [ModuleTest] has these constructors:

Constructor	Result
[ModuleTest]	Loads no module from the attribute. The test can get modules from module attributes.
[ModuleTest(typeof(ShopModule))]	Loads one module.
[ModuleTest(typeof(ShopModule), typeof(MailModule))]	Loads the modules in the sequence of the list.

The constructor with two or more module types does not record the source file and the line of the test. Thus the test explorer of an IDE cannot open the source code of this test. The other two constructors record this information.

[ModuleTest] is an xUnit FactAttribute. Thus Skip, SkipType, SkipUnless, SkipWhen, SkipExceptions, Explicit, Timeout, DisplayName, and traits have the same function as on [Fact].

using DependencyModules.xUnit.Attributes;
using Shop;
using Xunit;

namespace Shop.Tests;

public class CalculatorTests
{
    [ModuleTest(typeof(ShopModule))]
    public void Multiplies(IPriceCalculator calculator)
    {
        Assert.Equal(6m, calculator.Total(2m, 3));
    }

    [ModuleTest(typeof(ShopModule), Skip = "Not ready")]
    public void SkippedTest(IPriceCalculator calculator) { }
}

The service provider gives values only to the parameters of the test method. xUnit gives the values for the constructor of the test class.

Data rows

You can use xUnit data attributes with [ModuleTest], for example [InlineData], [MemberData], and [ClassData]. The test package also reads other attributes that implement the xUnit IDataAttribute interface. The test package gives the values of a row to the first parameters of the method. The service provider gives the values for the other parameters.

using DependencyModules.xUnit.Attributes;
using Shop;
using Xunit;

namespace Shop.Tests;

public class RowTests
{
    [ModuleTest(typeof(ShopModule))]
    [InlineData(2, 4)]
    [InlineData(3, 6)]
    public void RowAndService(int quantity, int expected, IPriceCalculator calculator)
    {
        Assert.Equal(expected, calculator.Total(2m, quantity));
    }
}

Each row gets a new service provider. If the data attributes give no rows, the test fails. It does not pass when no row runs.

A row of the type TheoryData<T> or TheoryDataRow<T> has a type for each value. The xUnit analyzer compares the number of these types with the number of parameters. If the number of types is less, the analyzer gives the error xUnit1037. For a [ModuleTest] method, this number of values is correct.

Disable xUnit1037 for these tests:

using DependencyModules.xUnit.Attributes;
using Shop;
using Xunit;

namespace Shop.Tests;

public class TypedRowTests
{
    public static TheoryData<int> Quantities => new(2, 3);

#pragma warning disable xUnit1037

    [ModuleTest(typeof(ShopModule))]
    [MemberData(nameof(Quantities))]
    public void TypedRow(int quantity, IPriceCalculator calculator)
    {
        Assert.Equal(2m * quantity, calculator.Total(2m, quantity));
    }

#pragma warning restore xUnit1037
}

A TheoryDataRow can set its Skip, SkipType, SkipUnless, SkipWhen, Timeout, Traits, TestDisplayName, and Label. These values are applicable only to that row.

The test of a data row gets the traits of the class, of the method, and of the row. The traits of the row are, for example, from the Traits property of [InlineData]. A [Theory] row gets its traits in the same way.

Lifetime of the service provider

The test package builds the service providers when xUnit makes the tests of a test method. After all tests of the test method run, the test package disposes these service providers.

Test information

The ITestCaseInfo interface in the DependencyModules.xUnit.Impl namespace has these properties:

Property	Value
TestMethod	The xUnit IXunitTestMethod.
TestMethodArguments	The values of the parameters.
TestMethodAttributes	The attributes of the test method, the test class, and the assembly.

using DependencyModules.xUnit.Attributes;
using DependencyModules.xUnit.Impl;
using Xunit;

namespace Shop.Tests;

public class InfoTests
{
    [ModuleTest]
    public void KnowsItsName(ITestCaseInfo info)
    {
        Assert.Equal(nameof(KnowsItsName), info.TestMethod.MethodName);
    }
}

Code that does not get the test as a parameter can use CurrentTest. In xUnit, CurrentTest has no test while the test package builds the service provider. For more information, refer to CurrentTest and test output.