WorkerHttpFake

Fake test data builder for HttpRequestData objects.

This library allows you to create faked HttpRequestData objects which can be used for integration testing Azure Isolated Worker Functions, providing a builder (HttpRequestDataBuilder) that allows you to specify properties such as Headers, Body, Queries, Cookies, etc.

Background

There isn't an official Azure integration test example with the new HttpRequestData input for Azure Isolated Worker Functions which has been mentioned in Issue items with the Azure team:

• 2263
• 541
• 304
• 281

Without an official 'elegant' solution presented, this library offers a fluent wrapper for a faked implementation of HttpRequestData which covered my personal use cases.

The code has been based on comments in the above issues and inspired by the below libraries (thanks to @lohithgn and @simon-k) for creating a .NET 8 implementation:

• https://github.com/lohithgn/az-fx-isolated-unittest
• https://github.com/simon-k/fake-http-request-data/

Examples

The below examples result in a HttpRequestData object being built based on the configured builder options; this can be used for integration tests or with Moq unit tests against your Azure Function.

In the WorkerHttpFake.Test test project there are examples of each method and how to implement this with Moq against an Azure Isolated Worker Function.

URL and Query Params

Below is a GET request featuring a custom URL with a query param:

string endpoint = "https://your-api/api/stores?sortBy=Nearest"

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithUrl(endpoint)
        .Build();

Query params can then be extracted from the Query field from the function HttpRequestData parameter e.g. req.Headers["sortBy"].

This alternatively could have been specified as following:

string endpoint = "https://your-api/api/stores"

NameValueCollection queryParams = new()
{
	{ "sortBy", "Nearest" }
};

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithUrl(endpoint)
	.WithQueryParams(endpoint)
        .Build();

Specifying WithUrl is not mandatory and will default to "http://localhost/" if not set, i.e. in the case of unit tests where Moq is used and URL may be irrelevant.

Headers

You can set the Authorization header for basic authorization requests as follows:

string basicAuthData = "ZGVtbzpwQDU1dzByZA==";

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithBasicAuthorization(basicAuthData)
        .Build();

Or if you are using Bearer or digest, their methods (WithBearerAuthorization and WithDigestAuthorization) are called the same way with a string value.

Alternatively you can set headers yourself, including:

string basicAuthData = "ZGVtbzpwQDU1dzByZA==";

NameValueCollection headers = new()
{
	{ "Custom-Header-1", "one" },
        { "Custom-Header-2", "two" },
	{ "Authorization", basicAuthData }
};

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithHeaders(headers)
        .Build();

The WithHeaders method replaces all headers, so the authorization method should be chained afterwards:

string basicAuthData = "ZGVtbzpwQDU1dzByZA==";

NameValueCollection headers = new()
{
	{ "Custom-Header-1", "one" },
        { "Custom-Header-2", "two" }
};

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithHeaders(headers)
	.WithBasicAuthorization(basicAuthData)
        .Build();

Body and Method

Below is an example POST request with a JSON body:

string jsonBody = JsonConvert.SerializeObject(new
{
	id = 1,
        example = "one"
});

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithMethod(HttpMethod.Post)
	.WithBody(jsonBody)
        .Build();

If your application validates Content-Type you can chain .WithHeaders as described in Headers.

Binding Context

Similar to Http Headers, you may also set the custom Function Context binding data:

NameValueCollection contextData = new()
{
	{ "Custom-Header-1", "one" },
        { "Custom-Header-2", "two" }
};

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithBindingContextData(contextData)
        .Build();

Cookies

You can set cookies in your request as follows:

List<IHttpCookie> cookies = [
	new HttpCookie("CookieName", "CookieValue")
];

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithCookies(cookies)
        .Build();

Identities

You can set a collection of Identity claims as follows:

List<ClaimsIdentity> identities = [
	new ClaimsIdentity(
        [
        	new Claim(ClaimTypes.Name, "ExampleName"),
                new Claim(ClaimTypes.Email, "ExampleEmail")
	])
];

HttpRequestData requestData = new HttpRequestDataBuilder()
	.WithIdentities(identities)
        .Build();

Custom Function Context

If you have an advanced middleware use case, you can provide your own FunctionContext data, though at that point you may want to derive a new class from HttpRequestData in your own implementation - here is a more basic example:

Dictionary<string, object> bindingData = new()
{
	{ "MockBindingData", "123" }
};

Mock<FunctionContext> functionContext = new();

IHost workersHost = new HostBuilder()
	.ConfigureFunctionsWebApplication()
        .Build();

functionContext.Setup(x => x.InstanceServices).Returns(workersHost.Services);
functionContext.SetupGet(x => x.BindingContext.BindingData).Returns(bindingData);

HttpRequestData request = new HttpRequestDataBuilder()
	.WithCustomContext(functionContext.Object)
        .Build();