Trigger handle-pr-push on PR updates

This is the final bit of the migration from GitGitGadget's Azure
Pipelines to GitHub workflows.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

GitGitGadget/index.js

@@ -43,6 +43,17 @@ module.exports = async (context, req) => {
                 status: 403,
                 body: 'Refusing to work on a repository other than gitgitgadget/git or git/git'
             };
+        } else if (eventType === 'pull_request') {
+            if (req.body.action !== 'opened' && req.body.action !== 'synchronize') {
+                context.res = {
+                    body: `Ignoring pull request action: ${req.body.action}`,
+                };
+            } else {
+                const run = await triggerWorkflowDispatch(...a, 'handle-pr-push.yml', 'main', {
+                    'pr-url': req.body.pull_request.html_url
+                })
+                context.res = { body: `Okay, triggered ${run.html_url}!` };
+            }
         } else if ((new Set(['check_run', 'status']).has(eventType))) {
             context.res = {
                 body: `Ignored event type: ${eventType}`,

__tests__/index.test.js

@@ -275,4 +275,34 @@ testWebhookPayload('react to `lore-1` being pushed to https://github.com/gitgitg
         'main',
         undefined
     ])
+})
+testWebhookPayload('react to PR push', 'pull_request', {
+    action: 'synchronize',
+    pull_request: {
+        html_url: 'https://github.com/gitgitgadget/git/pull/1956',
+    },
+    repository: {
+        full_name: 'gitgitgadget/git',
+        owner: {
+            login: 'gitgitgadget'
+        }
+    }
+}, (context) => {
+    expect(context.res).toEqual({
+        body: [
+            'Okay, triggered <the URL to the workflow handle-pr-push.yml run on main with inputs',
+            '{"pr-url":"https://github.com/gitgitgadget/git/pull/1956"}>!'
+        ].join(' ')
+    })
+    expect(mockTriggerWorkflowDispatch).toHaveBeenCalledTimes(1)
+    expect(mockTriggerWorkflowDispatch.mock.calls[0]).toEqual([
+        context,
+        undefined,
+        'gitgitgadget-workflows',
+        'gitgitgadget-workflows',
+        'handle-pr-push.yml',
+        'main', {
+            'pr-url': 'https://github.com/gitgitgadget/git/pull/1956',
+        }
+    ])
 })