move GitHub specific to its own class

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

__tests__/github.test.ts

@@ -0,0 +1,53 @@
+import {describe, expect, jest, it, beforeEach, afterEach} from '@jest/globals';
+
+import {GitHub, GitHubRepo} from '../src/github';
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
+import * as repoFixture from './fixtures/repo.json';
+jest.spyOn(GitHub.prototype, 'repoData').mockImplementation((): Promise<GitHubRepo> => {
+  return <Promise<GitHubRepo>>(repoFixture as unknown);
+});
+
+describe('context', () => {
+  it('returns repository name from payload', async () => {
+    const github = new GitHub();
+    expect(github.context.payload.repository?.name).toEqual('test-docker-action');
+  });
+  it('is repository private', async () => {
+    const github = new GitHub();
+    expect(github.context.payload.repository?.private).toEqual(true);
+  });
+});
+
+describe('serverURL', () => {
+  const originalEnv = process.env;
+  beforeEach(() => {
+    jest.resetModules();
+    process.env = {
+      ...originalEnv,
+      GITHUB_SERVER_URL: 'https://foo.github.com'
+    };
+  });
+  afterEach(() => {
+    process.env = originalEnv;
+  });
+  it('returns default', async () => {
+    process.env.GITHUB_SERVER_URL = '';
+    const github = new GitHub();
+    expect(github.serverURL).toEqual('https://github.com');
+  });
+  it('returns from env', async () => {
+    const github = new GitHub();
+    expect(github.serverURL).toEqual('https://foo.github.com');
+  });
+});
+
+describe('repoData', () => {
+  it('returns GitHub repository', async () => {
+    const github = new GitHub();
+    expect((await github.repoData()).name).toEqual('Hello-World');
+  });
+});