Fake Client (feature request)

[RafaeLeal]

Hi!
My team has been using this client a lot to integrate our new CICD tool (Tekton) with Github. Thanks, btw! It mostly "just works" :)
To test these integrations, we implemented a simple fake client. I'd like to ask if a PR adding a fake client would be welcome.
This would require us to add interfaces for the client and its services..

Just a quick view of how that would look like:

package github

import (
	"context"
	"net/http"
)

type ChecksServiceInterface interface {
	//TODO finish me
	GetCheckRun(ctx context.Context, owner, repo string, checkRunID int64) (*CheckRun, *Response, error)
	CreateCheckRun(ctx context.Context, owner, repo string, opts CreateCheckRunOptions) (*CheckRun, *Response, error)
	UpdateCheckRun(ctx context.Context, owner, repo string, checkRunID int64, opts UpdateCheckRunOptions) (*CheckRun, *Response, error)
	ListCheckRunsCheckSuite(ctx context.Context, owner, repo string, checkSuiteID int64, opts *ListCheckRunsOptions) (*ListCheckRunsResults, *Response, error)
}

type RepositoriesServiceInterface interface {
	//TODO finish me
	ListHooks(ctx context.Context, owner, repo string, opts *ListOptions) ([]*Hook, *Response, error)
}

type IssuesServiceInterface interface {
	//TODO finish me
	CreateComment(ctx context.Context, owner string, repo string, number int, comment *IssueComment) (*IssueComment, *Response, error)
}

type Interface interface {
	//TODO finish me
	ChecksService() ChecksServiceInterface
	RepositoriesService() RepositoriesServiceInterface
	IssuesService() IssuesServiceInterface
	RateLimits(ctx context.Context) (*RateLimits, *Response, error)
}

func NewClientInterface(httpClient *http.Client) Interface {
	return NewClient(httpClient)
}

func (g *Client) ChecksService() ChecksServiceInterface {
	return g.Checks
}

func (g *Client) RepositoriesService() RepositoriesServiceInterface {
	return g.Repositories
}

func (g *Client) IssuesService() IssuesServiceInterface {
	return g.Issues
}

Then you could use the client though the interfaces:

githubClient := github.NewClientInterface(nil) // type github.Interface
_, _, err := githubClient.ChecksService().CreateCheckRun(...)
...

And it would be the same for fake client

githubClient := fakegithub.NewFakeClient(nil) // type github.Interface
_, _, err := githubClient.ChecksService().CreateCheckRun(...)
...

[gmlewis]

Thank you, @RafaeLeal - this sounds cool! Before we proceed any further, could you please take a moment and read through #1800 since I think that is relevant.

We might recommend creating your fakegithub client in a separate repo (under your own corporate or personal GitHub username). Please let us know what you think after reading that discussion. (Sorry, but the discussion itself got branched out all over the place.)

[RafaeLeal]

Thanks for the link, I read some of the discussion..

In my case, I don't need to embed interfaces into the struct, but I'd benefit from having interfaces for the client.
Although I could (and we already did actually) add interfaces on our side, I can not implement methods for the GitHub client.
So if we want to have a GitHub client interface as I showed I need to write a wrapper for the GitHub client.

type githubClient struct {
	client *github.Client
}

func New() (Interface, error) {
	gh, err := client.NewGithubClient()
	if err != nil {
		return nil, err
	}
	return &githubClient{client: gh}, nil
}

func (g *githubClient) ChecksService() ChecksServiceInterface {
	return g.client.Checks
}

func (g *githubClient) RepositoriesService() RepositoriesServiceInterface {
	return g.client.Repositories
}

func (g *githubClient) IssuesService() IssuesServiceInterface {
	return g.client.Issues
}

and this type of code seems a bad smell since it's going to require us to keep with the changes inside this repo.

I can't simply use

githubClient := github.NewClient(nil) // returns *github.Client
githubClient.Checks.CreateCheckRun(...)

because we need the interfaces to fake them

[migueleliasweb]

Hi @RafaeLeal , after lots of conversations and feedback about this topic from the folks from go-github, I've help create a separate repo to address this functionality. I had a similar issue as I needed to unittest my code that uses the go-github SDK. Cheers!

Have a look: https://github.com/google/go-github#testing-code-that-uses-go-github

[gmlewis]

Closing feature request. Please let us know (or submit a PR that updates README.md) if you decide to create another external helper repo that we can point to, @RafaeLeal .