Merge pull request #472 from seamuslee001/testing_docs

Update Jenkins Documention to resolve issue #458

docs/testing/continuous-integration.md

-## Jenkins
+# Jenkins
 
-To prevent defects from entering the system or remaining in the system, 
-the tests are executed automatically by Jenkins - our continuous integration server.
+Jenkins is CiviCRM's [continuous integration](https://en.wikipedia.org/wiki/Continuous_integration) server.
 
-The test system runs twice. Firstly, when a change is proposed through Github 
-(as a "pull-request" or "PR"), Jenkins tests it immediately. (This takes 5-90min.) 
+To prevent defects from entering the system or remaining in the system, the tests are executed automatically by Jenkins. Jenkins first runs php and javascript style checks through the usage of `civilint` before running unit tests.
 
-Unfortunately, the full test suite would take several hours longer, so Jenkins 
-only runs some tests at this stage. 
+Jenkins runs two different types of jobs a PR test job and a matrix Job. The results of the tests are published at [test.civicrm.org](https://test.civicrm.org) There is some additional documenation in the [testing-readme](https://github.com/civicrm/civicrm-core/blob/master/tests/README.md)
 
-The results of the tests are published at [test.civicrm.org][jenkins-test-results]
+## Jenkins Whitelist
 
-If the tests have failed for something that we suspect is a random failure, we
-can ask Jenkins to run the tests again by commenting in the PR "Jenkins, test
-this please" 
+For new (unrecognised by Jenkins) contributors, Jenkins will automatically respond "can an admin verify this patch?", and a Github user with admin permissions may approve running the tests by commenting on the PR "ok to test".
 
-Jenkins only builds a Drupal site that is built against the branch that your
-PR is modifying.  If you need to test a patch against another CMS than you
-will want to test the patch in your own environment.
+If the user is trusted, CiviCRM administrators can add the person to the whitelist by commenting "add to whitelist".
 
-## Jenkins Whitelist 
+## PR Test Jobs
 
-For new (unrecognised by Jenkins) contributors, Jenkins will automatically
-respond "can an admin verify this patch?", and a Github user with admin
-permissions may approve running the tests by commenting on the PR "ok to test".
+Jenkins runs a "PR Test" job which is triggered whenever a pull request is created or updated in GitHub. PR test jobs can take anywhere from 5 - 90 min to complete. This works for the following repos:
 
-If the user is trusted, CiviCRM administrators can add the person to the
-whitelist by commenting "add to whitelist".
+* `civicrm-core`
+* `civicrm-packages`
+* `civicrm-drupal`
+* `civicrm-backdrop`
 
-## Build Schedule
+Jenkins runs a mix of [PHPUnit](/testing/phpunit.md#suites) [PHPWebTests](/testing/selenium.md) and [Javascript UnitTests](/testing/karma.md). The details of the types of suites and purpose can be found on the index of this [chapter](/testing/index.md)
 
-Jenkins periodically runs the full suite (once every 4-24hr) on the official 
-codebase.
- 
-Code-style is not checked on this build, but all upgrade and web tests are run.
+To run all the tests in one of the suites locally, you can use [civi-test-run](/tools/civi-test-run.md).
+
+The tests that are run are variable depending on the repository that is triggered.
+
+* `civicrm-core`: Upgrade, karma, CRM, api_v3, E2E and Civi tests
+* `civicrm-packages`: same as civicrm-core
+* `civicrm-drupal`: Upgrade, Karma and E2E tests
+* `civicrm-backdrop`: same as civicrm-drupal
+
+For PR test jobs against `civicrm-core` and `civicrm-packages`, Jenkins only builds a Drupal site to run the tests against. If you are fixing an issue with another CMS you may need to build yourself a local test environment with that CMS
+
+If the tests have failed for something that we suspect is a random failure, we can ask Jenkins to run the tests again by commenting in the PR "Jenkins, test this please"
+
+## Matrix Test Jobs
+
+The other type of Job that jenkins runs is what is described as a "matrix" job. This is a much more extended version of the PR job and is usually run against multiple different webserver configurations.
 
-## Running the test suite locally
+The main difference between the `CiviCRM-Core-Matrix` job and a PR test job is that it runs more upgrade tests than the `CiviCRM-Core-PR`.
+
+The other matrix job is one that runs the webtests.
+
+The matrix jobs operate on two main combinations, a PHP5.5 + MySQL5.5 server and a PHP7.0 + MySQL5.7 test seerver.
+
+Due to the size of the test matrix, jobs can take from 2 to 24 hours to complete depending on the job.
+
+### Build Schedule
+
+Jenkins periodically runs the full suite (once every 4-24hr) on the official codebase.
+
+Code-style is not checked on this build, but all upgrade and web tests are run.
 
-You can use [civi-test-run](/tools/civi-test-run.md) locally to run a full standard CiviCRM Test suite.
 
-[jenkins-test-results]: https://test.civicrm.org/
-[testing-readme]: https://github.com/civicrm/civicrm-core/blob/master/tests/README.md