---
name: mstest-skill
description: >
  Generates MSTest tests in C#. Microsoft's built-in testing framework for .NET.
  Use when user mentions "MSTest", "[TestMethod]", "[TestClass]",
  "Assert.AreEqual". Triggers on: "MSTest", "[TestMethod]", "[TestClass]",
  "Microsoft test framework".
languages:
  - C#
category: unit-testing
license: MIT
metadata:
  author: TestMu AI
  version: "1.0"
---

# MSTest Testing Skill

## Core Patterns

### Basic Test

```csharp
using Microsoft.VisualStudio.TestTools.UnitTesting;

[TestClass]
public class CalculatorTests
{
    private Calculator _calc;

    [TestInitialize]
    public void SetUp() => _calc = new Calculator();

    [TestMethod]
    public void Add_TwoNumbers_ReturnsSum()
    {
        Assert.AreEqual(5, _calc.Add(2, 3));
    }

    [TestMethod]
    [ExpectedException(typeof(DivideByZeroException))]
    public void Divide_ByZero_Throws()
    {
        _calc.Divide(10, 0);
    }
}
```

### Data-Driven Tests

```csharp
[DataTestMethod]
[DataRow(2, 3, 5)]
[DataRow(-1, 1, 0)]
[DataRow(0, 0, 0)]
public void Add_Parameterized(int a, int b, int expected)
{
    Assert.AreEqual(expected, _calc.Add(a, b));
}

[DataTestMethod]
[DynamicData(nameof(GetTestData), DynamicDataSourceType.Method)]
public void Add_DynamicData(int a, int b, int expected)
{
    Assert.AreEqual(expected, _calc.Add(a, b));
}

private static IEnumerable<object[]> GetTestData()
{
    yield return new object[] { 1, 2, 3 };
    yield return new object[] { 10, -5, 5 };
}
```

### Assertions

```csharp
Assert.AreEqual(expected, actual);
Assert.AreNotEqual(unexpected, actual);
Assert.IsTrue(condition);
Assert.IsFalse(condition);
Assert.IsNull(obj);
Assert.IsNotNull(obj);
Assert.IsInstanceOfType(obj, typeof(MyClass));
Assert.ThrowsException<ArgumentException>(() => Method());
CollectionAssert.Contains(list, item);
CollectionAssert.AreEquivalent(expected, actual);
StringAssert.Contains(str, "substring");
StringAssert.StartsWith(str, "prefix");
StringAssert.Matches(str, new Regex(@"\d+"));
```

### Lifecycle

```
[AssemblyInitialize]  → Once per assembly (static)
[ClassInitialize]     → Once per class (static)
[TestInitialize]      → Before each test
[TestMethod]          → Test
[TestCleanup]         → After each test
[ClassCleanup]        → Once after class (static)
[AssemblyCleanup]     → Once after assembly (static)
```

### Categories

```csharp
[TestMethod, TestCategory("Smoke")]
public void QuickTest() { }

[TestMethod, Ignore("Bug #456")]
public void SkippedTest() { }

[TestMethod, Timeout(5000)]
public void TimedTest() { }
```

## Setup: `dotnet add package MSTest.TestFramework MSTest.TestAdapter Microsoft.NET.Test.Sdk`
## Run: `dotnet test` or `dotnet test --filter "TestCategory=Smoke"`

## Deep Patterns

See `reference/playbook.md` for production-grade patterns:

| Section | What You Get |
|---------|-------------|
| §1 Project Setup | .csproj deps, .runsettings with parallel + coverage config |
| §2 Test Patterns | TestMethod, DataTestMethod, DynamicData, exception testing |
| §3 FluentAssertions | AssertionScope, async exceptions, collection assertions |
| §4 Class & Assembly Initialize | Testcontainers, shared expensive setup, global config |
| §5 WebApplicationFactory | API integration tests with in-memory DB |
| §6 Bogus Test Data | Faker patterns for realistic data generation |
| §7 TestContext & Logging | Diagnostic output, categories, timeouts |
| §8 CI/CD Integration | GitHub Actions with coverage reporting and thresholds |
| §9 Debugging Table | 12 common problems with causes and fixes |
| §10 Best Practices | 14-item production checklist |

## Source and license

Source: https://github.com/LambdaTest/agent-skills/blob/0491a3a29aa18558d2c3c64ff09367adb976c56f/mstest-skill/SKILL.md

MIT License

Copyright (c) 2025 TestMu AI / LambdaTest

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.