Before return site domain & path, create the site

src/enable-pages.js

@@ -0,0 +1,31 @@
+const core = require('@actions/core')
+const axios = require('axios')
+
+async function enablePages({ repositoryNwo, githubToken }) {
+  const pagesEndpoint = `https://api.github.com/repos/${repositoryNwo}/pages`
+
+  try {
+    const response = await axios.post(
+      pagesEndpoint,
+      {
+        headers: {
+          Accept: 'application/vnd.github.v3+json',
+          Authorization: `Bearer ${githubToken}`,
+          'Content-type': 'application/json',
+        },
+        body: JSON.stringify({ build_type: 'workflow' }),
+      }
+    )
+    core.info('Created pages site')
+  } catch (error) {
+    if (error.response && error.response.status === 409) {
+      core.info('Pages site exists')
+      return
+    }
+
+    core.error('Couldn\'t create pages site', error)
+    throw error
+  }
+}
+
+module.exports = enablePages

src/enable-pages.test.js

@@ -0,0 +1,48 @@
+const core = require('@actions/core')
+const axios = require('axios')
+
+const enablePages = require('./enable-pages')
+
+describe('enablePages', () => {
+  const GITHUB_REPOSITORY = 'paper-spa/is-awesome'
+  const GITHUB_TOKEN = 'gha-token'
+
+  beforeEach(() => {
+    jest.restoreAllMocks()
+
+    // Mock error/warning/info/debug
+    jest.spyOn(core, 'error').mockImplementation(jest.fn())
+    jest.spyOn(core, 'warning').mockImplementation(jest.fn())
+    jest.spyOn(core, 'info').mockImplementation(jest.fn())
+    jest.spyOn(core, 'debug').mockImplementation(jest.fn())
+  })
+
+  it('makes a request to create a page', async () => {
+    jest
+      .spyOn(axios, 'post')
+      .mockImplementationOnce(() => Promise.resolve({  }))
+
+    await enablePages({ repositoryNwo: GITHUB_REPOSITORY, githubToken: GITHUB_TOKEN })
+  })
+
+  it('handles a 409 response when the page already exists', async () => {
+    jest
+      .spyOn(axios, 'post')
+      .mockImplementationOnce(() => Promise.reject({ response: { status: 409 } }))
+
+    // Simply assert that no error is raised
+    await enablePages({ repositoryNwo: GITHUB_REPOSITORY, githubToken: GITHUB_TOKEN })
+  })
+
+  it('re-raises errors on failure status codes', async () => {
+    jest
+      .spyOn(axios, 'post')
+      .mockImplementationOnce(() => Promise.reject({ response: { status: 404 } }))
+
+    try {
+      await enablePages({ repositoryNwo: GITHUB_REPOSITORY, githubToken: GITHUB_TOKEN })
+    } catch (error) {
+      expect(error.response.status).toEqual(404)
+    }
+  })
+})

src/index.js

@@ -1,5 +1,6 @@
 const core = require('@actions/core')
 
+const enablePages = require('./enable-pages')
 const getPagesBaseUrl = require('./get-pages-base-url')
 
 // All variables we need from the runtime are loaded here
@@ -8,6 +9,7 @@ const getContext = require('./context')
 async function main() {
   try {
     const context = getContext()
+    await enablePages(context)
     await getPagesBaseUrl(context)
   } catch (error) {
     core.setFailed(error)