[QGIS-Developer] Woohoo! Interactive Travis debugging

[Nyall Dawson]

Hey all,

Good news -- interactive debugging is now available on our Travis
account, which means that it's now possible to remotely login and
interactively run tests on Travis builds! This should save a stack of
frustration when things just don't act the same on Travis as they do
locally.

Quoting the email from Travis:

"Now you can start restarting your builds in Debug mode with an API
request. To trigger a debug job:

0. Get your API token from your profile page at: https://travis-ci.org/profile

1. Send a POST request to /job/:job_id/debug replacing the TOKEN and
JOB_ID values below:

#! /usr/bin/env bash
  curl -s -X POST \
   -H "Content-Type: application/json" \
   -H "Accept: application/json" \
   -H "Travis-API-Version: 3" \
   -H "Authorization: token <TOKEN>" \
   -d '{ "quiet": true }' \
   https://api.travis-ci.org/job/<JOB_ID>/debug

The Job ID is displayed in the build log after expanding "Build system
information".

2. Head back to the web UI and in the log of your job. There you
should see the following lines to connect to the VM:

Setting up debug tools.
Preparing debug sessions.
Use the following SSH command to access the interactive debugging environment:
ssh ukjiuCEkxBBnRAe32Y8xCH0zj at ny2.tmate.io

3. Connect from your computer using SSH into the interactive session,
and once you're done, just type exit and your build will terminate.

Once in the SSH session, these bash functions will come in handy to
run the different phases in your build:
https://docs.travis-ci.com/user/running-build-in-debug-mode/#Things-to-do-once-you-are-inside-the-debug-VM