spectre.console/docs/input/cli/unit-testing.md
2025-04-08 16:58:25 +02:00

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Title: Unit Testing
Order: 14
Description: Instructions for unit testing a Spectre.Console application.
Reference:
- T:Spectre.Console.Testing.CommandAppTester
- T:Spectre.Console.Testing.TestConsole
- T:Spectre.Console.Testing.TestConsoleInput
---
`Spectre.Console` has a separate project that contains test harnesses for unit testing your own console applications.
The fastest way of getting started is to install the `Spectre.Console.Testing` NuGet package.
```text
> dotnet add package Spectre.Console.Testing
```
`Spectre.Console.Testing` is also the namespace containing the test classes.
## Testing a CommandApp
The `CommandAppTester` is a test implementation of `CommandApp` that's configured in a similar manner but designed for unit testing.
The following example validates the exit code and terminal output of a `Spectre.Console` command:
```csharp
/// <summary>
/// A Spectre.Console Command
/// </summary>
public class HelloWorldCommand : Command
{
private readonly IAnsiConsole _console;
public HelloWorldCommand(IAnsiConsole console)
{
// nb. AnsiConsole should not be called directly by the command
// since this doesn't play well with testing. Instead,
// the command should inject a IAnsiConsole and use that.
_console = console;
}
public override int Execute(CommandContext context)
{
_console.WriteLine("Hello world.");
return 0;
}
}
[TestMethod]
public void Should_Output_Hello_World()
{
// Given
var app = new CommandAppTester();
app.SetDefaultCommand<HelloWorldCommand>();
// When
var result = app.Run();
// Then
Assert.AreEqual(result.ExitCode, 0);
Assert.AreEqual(result.Output, "Hello world.");
}
```
## Testing console behaviour
`TestConsole` and `TestConsoleInput` are testable implementations of `IAnsiConsole` and `IAnsiConsoleInput`, allowing you fine-grain control over testing console output and interactivity.
The following example renders some widgets before then validating the console output:
```csharp
[TestMethod]
public void Should_Render_Panel()
{
// Given
var console = new TestConsole();
// When
console.Write(new Panel(new Text("Hello World")));
// Then
Assert.AreEqual(console.Output, """"
┌─────────────┐
Hello World
└─────────────┘
"""");
}
```
While `Assert` is fine for validating simple output, more complex output may benefit from a tool like [Verify](https://github.com/VerifyTests/Verify).
The following example prompts the user for input before then validating the expected choice was made:
```csharp
[TestMethod]
public void Should_Select_Orange()
{
// Given
var console = new TestConsole();
console.Input.PushTextWithEnter("Orange");
// When
console.Prompt(
new TextPrompt<string>("Favorite fruit?")
.AddChoice("Banana")
.AddChoice("Orange"));
// Then
Assert.AreEqual(console.Output, "Favorite fruit? [Banana/Orange]: Orange\n");
}
```
`CommandAppTester` uses `TestConsole` internally, which in turn uses `TestConsoleInput`, offering a fully testable harness for `Spectre.Console` widgets, prompts and commands.