Changes

Page-load tests involve loading a specific web page and measuring the load performance (i.e. [https://wiki.mozilla.org/TestEngineering/Performance/Glossary#First_Non-Blank_Paint_.28fnbpaint.29 time-to-first-non-blank-paint], [https://wiki.mozilla.org/TestEngineering/Performance/Glossary#First_Contentful_Paint_.28fcp.29 first-contentful-paint] , [https://wiki.mozilla.org/TestEngineering/Performance/Glossary#DOM_Content_Flushed_.28dcf.29 dom-content-flushed], [https://wiki.mozilla.org/TestEngineering/Performance/Glossary#Time_To_First_Interactive_.28ttfi.29 ttfi]).

For page-load tests by default, instead of using live web pages for performance testing, Raptor uses a tool called [[https:/Mitmproxy/wiki.mozilla.org/TestEngineering/Performance/Raptor/Mitmproxy Mitmproxy]]. Mitmproxy allows us to record and playback test pages via a local Firefox proxy. The Mitmproxy recordings are stored on [https://github.com/mozilla/build-tooltool tooltool] and are automatically downloaded by Raptor when they are required for a test. Raptor uses mitmproxy via the [https://searchfox.org/mozilla-central/source/testing/mozbase/mozproxy mozbase mozproxy] package.

For warm page-load tests, the desktop browser (or android browser app) is just started up once; so the browser is warm on each page-load.