Fix BTCPay webhook not returning response

Adds a test for successful Webhook responses and fixes the missing
return.

app/routes/accounts/mastodon/btcpay_hook.ts

@@ -36,13 +36,15 @@ class MastodonBtcPayHookRoute extends BaseRoute {
       content: message
     }).then(() => res.status(200))
       .catch(err => this.handleError(res, err))
+
+    return res.status(200).json({ status: 'OK' })
   }
 
   private createMessage (inviteCode: String) {
     const inviteUrl = `${process.env.MASTODON_HOST}/invite/${inviteCode}`
     const message = 'Here\'s your invite link for creating an account on kosmos.social:'
                   + `\n\n${inviteUrl}\n\n`
-                  + 'Thanks a lot for supporting community service providers!'
+                  + 'Welcome to the community!'
     return message
   }
 

spec/routes/accounts/mastodon/btcpay_hook.spec.ts

@@ -6,6 +6,10 @@ setup()
 
 describe('POST /accounts/mastodon/btcpay_hook', () => {
 
+  before(() => {
+    process.env.BTCPAY_WEBHOOK_TOKEN = 'supersecure'
+  })
+
   describe('auth token missing', () => {
     it('returns an error', async () => {
       await supertest
@@ -32,4 +36,34 @@ describe('POST /accounts/mastodon/btcpay_hook', () => {
     })
   })
 
+  describe('successful request', () => {
+    before(() => {
+      sandbox
+        .stub(BaseRoute.prototype, 'createMastodonClient')
+        .returns({
+          post: url => {
+            return Promise.resolve({
+              data: { code: '123abc' }
+            })
+          }
+        })
+    })
+
+    it('returns an error', async () => {
+      await supertest
+        .post('/accounts/mastodon/btcpay_hook?token=supersecure')
+        .set('Content-Type', 'application/json')
+        .send({
+          buyerFields: {
+            buyerEmail: 'satoshi@kosmos.org'
+          },
+          status: 'confirmed'
+        })
+        .expect(200)
+        .then(res => {
+          expect(res.body.status).to.eq('OK')
+        })
+    })
+  })
+
 })