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https://github.com/HamedFathi/MockableStaticGenerator
A C# source generator to make an interface and a class wrapper to test static and extension methods.
https://github.com/HamedFathi/MockableStaticGenerator
csharp csharp-sourcegenerator csharp9 dotnet mock mocking sourcegenerator test testing
Last synced: about 2 months ago
JSON representation
A C# source generator to make an interface and a class wrapper to test static and extension methods.
- Host: GitHub
- URL: https://github.com/HamedFathi/MockableStaticGenerator
- Owner: HamedFathi
- License: mit
- Created: 2020-11-25T15:54:22.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2022-09-20T17:39:55.000Z (about 2 years ago)
- Last Synced: 2024-05-12T12:41:20.938Z (4 months ago)
- Topics: csharp, csharp-sourcegenerator, csharp9, dotnet, mock, mocking, sourcegenerator, test, testing
- Language: C#
- Homepage: https://hamedfathi.me/the-dotnet-world-csharp-source-generator/
- Size: 84 KB
- Stars: 14
- Watchers: 3
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
- RSCG_Examples - MockableStaticGenerator
- csharp-source-generators - MockableStaticGenerator -   A C# source generator to make an interface and a class wrapper to test static/extension methods. (Source Generators / Testing)
README
## Problem
I want to mock static or extensions methods. What should I do?
Sometimes I have those static methods inside my library and sometime they are in an external library like [Dapper](https://github.com/DapperLib/Dapper)
Do you have any solution?
## Solution
A good, well-known solution is writing a wrapper.
Consider the following example:
```cs
public class MyClass
{
public void LogMessage(string message)
{
Logger.Write(message);
}
}
public class Logger
{
public static void Write(string message)
{
//Write your code here to log data
}
}
```
You can use [Moq](https://github.com/moq/moq4) to mock non-static methods but it cannot be used to mock static methods, so what should I do if I want to mock `Logger.Write`?
#### Create a wrapper class and interface
Make an interface just like the signature of the static method
```cs
public interface IWrapper
{
void LogData(string message);
}
```
Implement that interface and call the static method (`Logger.Write`) into the same non-static method.
```cs
public class LogWrapper : IWrapper
{
string _message = null;
public LogWrapper(string message)
{
_message = message;
}
public void LogData(string message)
{
_message = message;
Logger.Write(_message);
}
}
```
Now you can use `IWrapper` and `LogWrapper` everywhere in your code and also make things mockable.
```cs
var mock = new Mock();
mock.Setup(x => x.LogData(It.IsAny()));
new ProductBL(mock.Object).LogMessage("Hello World!");
mock.VerifyAll();
```
#### What is the wrong part with this solution?
Of course, you can not do this for all static methods or for all external libraries. It is hard and tedious work. Maybe sometimes impossible!
## MockableStaticGenerator
`MockableStaticGenerator` is a C# code generator for making your static/extension methods even from an external library mockable just like above approach but automatically!
#### How it works?
* For internal usage
If you have a class with static methods inside it, put `[MockableStatic]` on top of the class
```cs
// For your class with some static methods.
[MockableStatic]
public class Math
{
public static int Add(int a, int b) { return a+b; }
public static int Sub(int a, int b) { return a+b; }
}
```
* For external usage
If you have a class with static methods inside it but from somewhere else (an external library for example), you should introduce **type of** that class to the `[MockableStatic]`
```cs
// For type of an external assembly with a lot of static methods
// like 'Dapper.SqlMapper' class in Dapper external library.
// It does not matter on top of what class it is, but Program class can be appropriate.
[MockableStatic(typeof(Dapper.SqlMapper))]
class Program
{
static void Main(string[] args)
{
// ...
}
}
```
#### How to call the generated interfaces and classes?
There are two naming conventions you should follow:
* `I{CLASS_NAME}Wrapper` for the interface
* `{CLASS_NAME}Wrapper` for the class
and you can find them under this namespace.
* namespace `MockableGenerated`
* `MockableGenerated.I{CLASS_NAME}Wrapper`
* `MockableGenerated.{CLASS_NAME}Wrapper`
#### Attention
You **must** use the generated interfaces and classes **instead of** the originals to make your library/application testable and mockable.
#### [Nuget](https://www.nuget.org/packages/MockableStaticGenerator)
[](https://opensource.org/licenses/MIT)
```
Install-Package MockableStaticGenerator
dotnet add package MockableStaticGenerator
```
For more details read [this blog post](https://hamedfathi.me/the-dotnet-world-csharp-source-generator/).