TestableIO.System.IO.Abstractions
21.1.3
Prefix Reserved
dotnet add package TestableIO.System.IO.Abstractions --version 21.1.3
NuGet\Install-Package TestableIO.System.IO.Abstractions -Version 21.1.3
<PackageReference Include="TestableIO.System.IO.Abstractions" Version="21.1.3" />
paket add TestableIO.System.IO.Abstractions --version 21.1.3
#r "nuget: TestableIO.System.IO.Abstractions, 21.1.3"
// Install TestableIO.System.IO.Abstractions as a Cake Addin #addin nuget:?package=TestableIO.System.IO.Abstractions&version=21.1.3 // Install TestableIO.System.IO.Abstractions as a Cake Tool #tool nuget:?package=TestableIO.System.IO.Abstractions&version=21.1.3
At the core of the library is IFileSystem
and FileSystem
. Instead of calling methods like File.ReadAllText
directly, use IFileSystem.File.ReadAllText
. We have exactly the same API, except that ours is injectable and testable.
Usage
dotnet add package TestableIO.System.IO.Abstractions.Wrappers
Note: This NuGet package is also published as System.IO.Abstractions
but we suggest to use the prefix to make clear that this is not an official .NET package.
public class MyComponent
{
readonly IFileSystem fileSystem;
// <summary>Create MyComponent with the given fileSystem implementation</summary>
public MyComponent(IFileSystem fileSystem)
{
this.fileSystem = fileSystem;
}
/// <summary>Create MyComponent</summary>
public MyComponent() : this(
fileSystem: new FileSystem() //use default implementation which calls System.IO
)
{
}
public void Validate()
{
foreach (var textFile in fileSystem.Directory.GetFiles(@"c:\", "*.txt", SearchOption.TopDirectoryOnly))
{
var text = fileSystem.File.ReadAllText(textFile);
if (text != "Testing is awesome.")
throw new NotSupportedException("We can't go on together. It's not me, it's you.");
}
}
}
Test helpers
The library also ships with a series of test helpers to save you from having to mock out every call, for basic scenarios. They are not a complete copy of a real-life file system, but they'll get you most of the way there.
dotnet add package TestableIO.System.IO.Abstractions.TestingHelpers
Note: This NuGet package is also published as System.IO.Abstractions.TestingHelpers
but we suggest to use the prefix to make clear that this is not an official .NET package.
[Test]
public void MyComponent_Validate_ShouldThrowNotSupportedExceptionIfTestingIsNotAwesome()
{
// Arrange
var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
{
{ @"c:\myfile.txt", new MockFileData("Testing is meh.") },
{ @"c:\demo\jQuery.js", new MockFileData("some js") },
{ @"c:\demo\image.gif", new MockFileData(new byte[] { 0x12, 0x34, 0x56, 0xd2 }) }
});
var component = new MyComponent(fileSystem);
try
{
// Act
component.Validate();
}
catch (NotSupportedException ex)
{
// Assert
Assert.That(ex.Message, Is.EqualTo("We can't go on together. It's not me, it's you."));
return;
}
Assert.Fail("The expected exception was not thrown.");
}
We even support casting from the .NET Framework's untestable types to our testable wrappers:
FileInfo SomeApiMethodThatReturnsFileInfo()
{
return new FileInfo("a");
}
void MyFancyMethod()
{
var testableFileInfo = (FileInfoBase)SomeApiMethodThatReturnsFileInfo();
...
}
Mock support
Since version 4.0 the top-level APIs expose interfaces instead of abstract base classes (these still exist, though), allowing you to completely mock the file system. Here's a small example, using Moq:
[Test]
public void Test1()
{
var watcher = Mock.Of<IFileSystemWatcher>();
var file = Mock.Of<IFile>();
Mock.Get(file).Setup(f => f.Exists(It.IsAny<string>())).Returns(true);
Mock.Get(file).Setup(f => f.ReadAllText(It.IsAny<string>())).Throws<OutOfMemoryException>();
var unitUnderTest = new SomeClassUsingFileSystemWatcher(watcher, file);
Assert.Throws<OutOfMemoryException>(() => {
Mock.Get(watcher).Raise(w => w.Created += null, new System.IO.FileSystemEventArgs(System.IO.WatcherChangeTypes.Created, @"C:\Some\Directory", "Some.File"));
});
Mock.Get(file).Verify(f => f.Exists(It.IsAny<string>()), Times.Once);
Assert.True(unitUnderTest.FileWasCreated);
}
public class SomeClassUsingFileSystemWatcher
{
private readonly IFileSystemWatcher _watcher;
private readonly IFile _file;
public bool FileWasCreated { get; private set; }
public SomeClassUsingFileSystemWatcher(IFileSystemWatcher watcher, IFile file)
{
this._file = file;
this._watcher = watcher;
this._watcher.Created += Watcher_Created;
}
private void Watcher_Created(object sender, System.IO.FileSystemEventArgs e)
{
FileWasCreated = true;
if(_file.Exists(e.FullPath))
{
var text = _file.ReadAllText(e.FullPath);
}
}
}
Related projects
System.IO.Abstractions.Extensions
provides convenience functionality on top of the core abstractions.System.IO.Abstractions.Analyzers
provides Roslyn analyzers to help use abstractions over static methods.Testably.Abstractions
provides alternative test helpers and additional abstractions.
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net5.0 was computed. net5.0-windows was computed. net6.0 is compatible. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 is compatible. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 is compatible. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. |
.NET Core | netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed. |
.NET Standard | netstandard2.0 is compatible. netstandard2.1 is compatible. |
.NET Framework | net461 was computed. net462 is compatible. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed. |
MonoAndroid | monoandroid was computed. |
MonoMac | monomac was computed. |
MonoTouch | monotouch was computed. |
Tizen | tizen40 was computed. tizen60 was computed. |
Xamarin.iOS | xamarinios was computed. |
Xamarin.Mac | xamarinmac was computed. |
Xamarin.TVOS | xamarintvos was computed. |
Xamarin.WatchOS | xamarinwatchos was computed. |
-
.NETFramework 4.6.2
- No dependencies.
-
.NETStandard 2.0
- No dependencies.
-
.NETStandard 2.1
- No dependencies.
-
net6.0
- No dependencies.
-
net7.0
- No dependencies.
-
net8.0
- No dependencies.
NuGet packages (21)
Showing the top 5 NuGet packages that depend on TestableIO.System.IO.Abstractions:
Package | Downloads |
---|---|
System.IO.Abstractions
A set of abstractions to help make file system interactions testable. |
|
TestableIO.System.IO.Abstractions.Wrappers
A set of abstractions to help make file system interactions testable. |
|
TestableIO.System.IO.Abstractions.TestingHelpers
A set of pre-built mocks to help when testing file system interactions. |
|
Testably.Abstractions.Interface
Interfaces for `Testably.Abstractions` to write testable code by abstracting away system dependencies. |
|
TestableIO.System.IO.Abstractions.Extensions
Convenience functionalities on top of System.IO.Abstractions |
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Version | Downloads | Last updated | |
---|---|---|---|
21.1.3 | 1,346 | 11/8/2024 | |
21.1.2 | 1,994 | 11/8/2024 | |
21.1.1 | 1,994 | 11/7/2024 | |
21.0.29 | 1,321,923 | 7/25/2024 | |
21.0.26 | 270,035 | 7/13/2024 | |
21.0.22 | 280,382 | 6/22/2024 | |
21.0.2 | 1,706,869 | 3/17/2024 | |
20.0.34 | 47,997 | 3/15/2024 | |
20.0.28 | 143,253 | 3/9/2024 | |
20.0.15 | 1,451,042 | 1/22/2024 | |
20.0.4 | 1,481,342 | 12/5/2023 | |
20.0.1 | 2,215 | 12/5/2023 | |
19.2.91 | 261,173 | 12/5/2023 | |
19.2.87 | 692,303 | 11/16/2023 | |
19.2.69 | 2,375,541 | 8/29/2023 | |
19.2.67 | 45,341 | 8/25/2023 | |
19.2.66 | 2,652 | 8/25/2023 | |
19.2.64 | 106,952 | 8/22/2023 | |
19.2.63 | 3,167 | 8/22/2023 | |
19.2.61 | 19,013 | 8/21/2023 | |
19.2.51 | 302,739 | 7/31/2023 | |
19.2.50 | 6,155 | 7/31/2023 | |
19.2.29 | 1,943,204 | 5/17/2023 | |
19.2.26 | 66,270 | 5/12/2023 | |
19.2.25 | 3,438 | 5/12/2023 | |
19.2.22 | 200,007 | 5/4/2023 | |
19.2.18 | 257,565 | 4/24/2023 | |
19.2.17 | 18,459 | 4/23/2023 | |
19.2.16 | 138,656 | 4/19/2023 | |
19.2.15 | 368,656 | 4/18/2023 | |
19.2.13 | 3,214 | 4/18/2023 | |
19.2.12 | 6,606 | 4/18/2023 | |
19.2.11 | 96,164 | 4/13/2023 | |
19.2.9 | 63,283 | 4/11/2023 | |
19.2.8 | 7,833 | 4/11/2023 | |
19.2.4 | 1,205,486 | 3/13/2023 | |
19.2.1 | 395,367 | 3/2/2023 | |
19.1.18 | 419,881 | 2/14/2023 | |
19.1.14 | 189,122 | 1/31/2023 | |
19.1.13 | 403,276 | 1/24/2023 | |
19.1.5 | 2,031,291 | 12/19/2022 | |
19.1.1 | 95,113 | 12/13/2022 | |
19.0.1 | 208,493 | 12/8/2022 | |
18.0.1 | 464,938 | 11/28/2022 | |
17.2.26 | 298,170 | 11/18/2022 |