From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- remote/doc/marionette/Debugging.md | 96 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 remote/doc/marionette/Debugging.md (limited to 'remote/doc/marionette/Debugging.md') diff --git a/remote/doc/marionette/Debugging.md b/remote/doc/marionette/Debugging.md new file mode 100644 index 0000000000..040db24c6e --- /dev/null +++ b/remote/doc/marionette/Debugging.md @@ -0,0 +1,96 @@ +# Debugging + +## Redirecting the Gecko output + +The most common way to debug Marionette, as well as chrome code in +general, is to use `dump()` to print a string to stdout. In Firefox, +this log output normally ends up in the gecko.log file in your current +working directory. With Fennec it can be inspected using `adb logcat`. + +`mach marionette-test` takes a `--gecko-log` option which lets +you redirect this output stream. This is convenient if you want to +“merge” the test harness output with the stdout from the browser. +Per Unix conventions you can use `-` (dash) to have Firefox write +its log to stdout instead of file: + +```shell +% ./mach marionette-test --gecko-log - +``` + +It is common to use this in conjunction with an option to increase +the Marionette log level: + +```shell +% ./mach test --gecko-log - -vv TEST +``` + +A single `-v` enables debug logging, and a double `-vv` enables +trace logging. + +This debugging technique can be particularly effective when combined +with using [pdb] in the Python client or the JS remote debugger +that is described below. + +[pdb]: https://docs.python.org/3/library/pdb.html + +## JavaScript debugger + +You can attach the [Browser Toolbox] JavaScript debugger to the +Marionette server using the `--jsdebugger` flag. This enables you +to introspect and set breakpoints in Gecko chrome code, which is a +more powerful debugging technique than using `dump()` or `console.log()`. + +To automatically open the JS debugger for `Mn` tests: + +```shell +% ./mach marionette-test --jsdebugger +``` + +It will prompt you when to start to allow you time to set your +breakpoints. It will also prompt you between each test. + +You can also use the `debugger;` statement anywhere in chrome code +to add a breakpoint. In this example, a breakpoint will be added +whenever the `WebDriver:GetPageSource` command is called: + +```javascript + GeckoDriver.prototype.getPageSource = async function() { + debugger; + … + } +``` + +To be prompted at the start of the test run or between tests, +you can set the `marionette.debugging.clicktostart` preference to +`true` this way: + +```shell +% ./mach marionette-test --setpref='marionette.debugging.clicktostart=true' --jsdebugger +``` + +For reference, below is the list of preferences that enables the +chrome debugger for Marionette. These are all set implicitly when +`--jsdebugger` is passed to mach. In non-official builds, which +are the default when built using `./mach build`, you will find that +the chrome debugger won’t prompt for connection and will allow +remote connections. + +* `devtools.browsertoolbox.panel` -> `jsdebugger` + + Selects the Debugger panel by default. + +* `devtools.chrome.enabled` → true + + Enables debugging of chrome code. + +* `devtools.debugger.prompt-connection` → false + + Controls the remote connection prompt. Note that this will + automatically expose your Firefox instance to localhost. + +* `devtools.debugger.remote-enabled` → true + + Allows a remote debugger to connect, which is necessary for + debugging chrome code. + +[Browser Toolbox]: /devtools-user/browser_toolbox/index.rst -- cgit v1.2.3