create a little MockGitHub class for tests mocking out the github REST API

[jstrachan]

there's a few projects I'd really like a simple mock implementation of GitHub for easier testing.

I'm fine with it being pretty basic (and defaulting to just not finding stuff ;) but if it was able to find users/orgs/repos/PRs and whatnot from in memory objects it'd be super handy.

I started a little spike using a real JAXRS server side and tried reusing the DTOs from this excellent library; but the way the DTOs work they are kinda hard wired into the Requestor; so figure it was maybe simplest to just add a little MockGitHub derived class. By barely changing the code I was able to get something basic going without breaking the GitHub API or implementation.

I can submit a little PR to show you the kinda thing am thinking. Its kinda an extension of the offline mode but just with a custom API that lets you populate some resources etc

[jstrachan]

@kohsuke what do you think of the general idea? I've got a little spike going but thought I'd wait for your thoughts before i go further. Can query/add users/orgs so far - gotta figure out how to support creating repos etc...

[jgangemi]

couldn't you do this w/ wiremock and return canned json responses?

either way, i support this idea!

[ometa]

This would be an excellent addition.

[jstrachan]

Here's my first spike https://github.com/jstrachan/github-api/tree/mock-api

e.g. https://github.com/jstrachan/github-api/blob/mock-api/src/test/java/org/kohsuke/github/mock/MockGitHubTest.java#L45

so we can create a mock user + list the repos for the user & create a new repository. There's an issue printing out the repository though (ownerName issues) due to:

estUser(org.kohsuke.github.mock.MockGitHubTest)  Time elapsed: 0.303 sec  <<< ERROR!
java.lang.NullPointerException
	at org.kohsuke.github.GHRepository.getOwnerName(GHRepository.java:355)
	at org.kohsuke.github.GHRepository.hashCode(GHRepository.java:1571)
	at java.util.WeakHashMap.hash(WeakHashMap.java:298)
	at java.util.WeakHashMap.put(WeakHashMap.java:449)
	at org.apache.commons.lang.builder.ToStringStyle.register(ToStringStyle.java:181)
	at org.apache.commons.lang.builder.ToStringStyle.appendClassName(ToStringStyle.java:1443)
	at org.apache.commons.lang.builder.ToStringStyle.appendStart(ToStringStyle.java:368)
	at org.apache.commons.lang.builder.ToStringBuilder.<init>(ToStringBuilder.java:266)
	at org.apache.commons.lang.builder.ReflectionToStringBuilder.<init>(ReflectionToStringBuilder.java:539)
	at org.kohsuke.github.GHObject$1.<init>(GHObject.java:108)
	at org.kohsuke.github.GHObject.toString(GHObject.java:108)
	at java.lang.String.valueOf(String.java:2994)
	at java.lang.StringBuilder.append(StringBuilder.java:131)
	at org.kohsuke.github.mock.MockGitHubTest.testUser(MockGitHubTest.java:58)

[kohsuke]

@jstrachan , my apologies for the delay. Yes, I think better testability would be great, and ability to mock things would be wonderful. I think @stephenc worked in some Jenkins plugins to extensively mock GH*** objects from literal JSON files. How can I help make this happen?