public void CombineAMiddlewareAndAFuncShouldReturnAFuncThatCombinesThem()
{
// Given
var calls = new List <string>();
SyncMiddlewareFunc <string, int> func = str =>
{
calls.Add("Func");
return(str.Length);
};
SyncMiddleware <string, int> middleware = (str, next) =>
{
calls.Add("Before");
var result = next(str);
calls.Add("After");
return(result);
};
var context = "Hello world!";
// When
var result = middleware.Combine(func)(context);
// Then
result.Should().Be(context.Length);
calls.Should().Equal("Before", "Func", "After");
}
public void ComposingMiddlewaresShouldProducesACompositeMiddleware()
{
// Given
var calls = new List <string>();
SyncMiddlewareFunc <string, int> func = str =>
{
calls.Add("Func");
return(str.Length);
};
SyncMiddleware <string, int> MakeMiddleware(int count)
{
return((str, next) =>
{
calls !.Add("Before" + count);
var result = next(str);
calls.Add("After" + count);
return result;
});
}
var middleware1 = MakeMiddleware(1);
var middleware2 = MakeMiddleware(2);
var middleware3 = MakeMiddleware(3);
var context = "Hello world!";
// When
var middleware = middleware1.Compose(middleware2, middleware3);
var result = func.Combine(middleware)(context);
// Then
result.Should().Be(context.Length);
calls.Should().Equal("Before1", "Before2", "Before3", "Func", "After3", "After2", "After1");
}
public static SyncMiddlewareFunc <TContext, TResult> Combine <TContext, TResult>(
this SyncMiddleware <TContext, TResult> middleware,
SyncMiddlewareFunc <TContext, TResult> func) =>
context => middleware(context, func);
