Re: Storage in Gecko

2013-04-26 Thread Andrew Sutherland
On 04/26/2013 03:21 PM, Dirkjan Ochtman wrote: Also, I wonder if SQLite 4 (which is more like a key-value store) SQLite 4 is not actually more like a key-value store. The underlying storage model used by the SQL-interface-that-is-the-interface changed from being a page-centric btree

Re: Storage in Gecko

2013-04-26 Thread Andrew Sutherland
On 04/26/2013 03:30 PM, Gregory Szorc wrote: However, before that happens, I'd like some consensus that IndexedDB is the best solution here. I'd especially like to hear what Performance thinks: I don't want to start creating a preferred storage solution without their blessing. If they have

Re: Code Review Session

2013-05-24 Thread Andrew Sutherland
On 05/24/2013 11:05 AM, Mike Conley wrote: Sounds like we're talking about code review. But I want to qualify integration into bugzilla: I explicitly do not want a tool that is tightly coupled to bugzilla. In fact, I want a tool that has as little to do with bugzilla as feasible. I'm a

Best way to make xpcshell provide consistent stack limits?

2013-06-26 Thread Andrew Sutherland
For B2G's gaia repository we are currently using xpcshell[1] as our command line JS runner. I was noticing some horrible inconsistencies in terms of blowing the JS stack when we were trying to use the esprima JS parser[2] that varied by the platform and build type. The nutshell is that the

Re: Best way to make xpcshell provide consistent stack limits?

2013-06-28 Thread Andrew Sutherland
On 06/28/2013 06:52 PM, Benjamin Smedberg wrote: The JS stack limit should be basically the native stack limit minus a little bit of headroom (maybe 512 bytes?). Whether we implement that dynamically or just use ifdefs to hardcode the correct values seems like just an implementation question.

Re: #ifdefing out mailnews-only code but keeping it in m-c

2013-11-11 Thread Andrew Sutherland
On 11/11/2013 01:33 PM, Joshua Cranmer  wrote: By far the easiest solution would be leaving the code in m-c but #ifdefing it out of Firefox builds. Is there a compelling reason not to do so? If there is no compelling reason against #ifdefing it out in m-c, what's the right variable to #ifdef on

Re: #ifdefing out mailnews-only code but keeping it in m-c

2013-11-13 Thread Andrew Sutherland
On 11/12/2013 03:39 AM, Henri Sivonen wrote: On Mon, Nov 11, 2013 at 10:08 PM, Andrew Sutherland asutherl...@asutherland.org wrote: On 11/11/2013 01:33 PM, Joshua Cranmer  wrote: Actually, I believe you need to keep the x-imap4-modified-utf7 converters in B2G, if you don't want to break Gaia

Possible to make all (CSS) transitions 0/1ms to speed up FxOS Gaia tests?

2014-02-16 Thread Andrew Sutherland
In Gaia, the system and many of the apps use transitions/animations with a non-trivial duration, particularly for card metaphor stuff where logic may be blocked on the completion of the animation. (Values seem to vary between 0.3s and 0.5s... no one tell UX!) Our Gaia tests currently take an

HTML sanitization, CSP, nsIContentPolicy, ServiceWorkers (was: Re: How to efficiently walk the DOM tree and its strings)

2014-03-05 Thread Andrew Sutherland
On 03/05/2014 01:52 AM, nsm.nik...@gmail.com wrote: On Tuesday, March 4, 2014 1:26:15 AM UTC-8, somb...@gmail.com wrote: While we have a defense-in-depth strategy (CSP and iframe sandbox should be protecting us from the worst possible scenarios) and we're hopeful that Service Workers will

Re: Too many system compartments at start-up

2014-03-21 Thread Andrew Sutherland
On 03/21/2014 12:06 PM, Bill McCloskey wrote: The problem with doing measurements is that the per-compartment overhead is very dependent on what's going on in the compartment. I tried to enable the B2G compartment merging stuff in desktop Firefox to get a sense of how much of a change there

Re: Spring cleaning: Reducing Number Footprint of HG Repos

2014-03-27 Thread Andrew Sutherland
On 03/27/2014 10:10 AM, Joshua Cranmer  wrote: It's worth noting that hg-git is having some performance issues with github right now. A basic clone of a 1MB repository takes well over a minute before it starts doing anything. When I was converting my repositories last night I found that

Re: Warning about mutating the [[Prototype]] of an object ?

2014-03-28 Thread Andrew Sutherland
The code should be fixed. It's my understanding that the existing idiom used throughout the Thunderbird tree is still okay to do since the prototype chain is created at object initialization time and so there's no actual mutation of the chain: function Application() { } Application.prototype

Re: Using rr to track down intermittent test failures

2014-04-16 Thread Andrew Sutherland
On 04/15/2014 07:14 PM, Gijs Kruitbosch wrote: 1) Is anyone working on something similar that works for frontend code (particularly, chrome JS)? I realize we have a JS debugger, but sometimes activating the debugger at the wrong time makes the bug go away, and then there's timing issues, and

B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-28 Thread Andrew Sutherland
tl;dr: We need to figure out how to safely allow for invalid certificates to be used in the Firefox OS Gaia email app. We do want all users to be able to access their email, but not by compromising the security of all users. Read on if you work in the security field / care about certificates

Re: B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-28 Thread Andrew Sutherland
. In the specific Mozilla case, this was probably https://bugzil.la/815771. Andrew Sutherland writes: I propose that we use a certificate-observatory-style mechanism to corroborate any invalid certificates by attempting the connection from 1 or more trusted servers whose identity can be authenticated using

Re: B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-28 Thread Andrew Sutherland
On 05/28/2014 08:37 PM, Karl Dubost wrote: Le 29 mai 2014 à 09:13, Andrew Sutherland asutherl...@asutherland.org a écrit : My imagined rationale for why someone would use a self-signed certificate amounts to laziness. being one of those persons using a self-signed certificate, let's enrich

Re: B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-29 Thread Andrew Sutherland
On 05/28/2014 09:30 PM, Brian Smith wrote: On Wed, May 28, 2014 at 5:13 PM, Andrew Sutherland I agree this is a safe approach and the trusted server is a significant complication in this whole endeavor. But I can think of no other way to break the symmetry of am I being attacked or do I just

Re: B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-29 Thread Andrew Sutherland
On 05/29/2014 07:12 PM, Brian Smith wrote: On Thu, May 29, 2014 at 2:03 PM, Andrew Sutherland asutherl...@asutherland.org wrote: It seems like you would be able to answer this as part of the scan of the internet, by trying to retrieve the self-hosted autoconfig file if it is available. I

Re: B2G, email, and SSL/TLS certificate exceptions for invalid certificates

2014-05-29 Thread Andrew Sutherland
On 05/28/2014 06:30 PM, Andrew Sutherland wrote: == Proposed solution for exceptions / allowing connections There are a variety of options here, but I think one stands above the others. I propose that we make TCPSocket and XHR with mozSystem take a dictionary that characterizes one or more

Re: Intent to implement: webserial api

2014-07-15 Thread Andrew Sutherland
On 07/13/2014 11:55 AM, Jonas Sicking wrote: Sadly I don't think that is very safe. I bet a significant majority of our users have no idea what a serial port is or what will happen if they allow a website to connect to it. Agreed. It seems like the concept users are most likely to reliably

Re: Intent to implement: webserial api

2014-07-16 Thread Andrew Sutherland
On 07/16/2014 02:03 PM, Dave Hylands wrote: But phones, and devices like the Raspberry Pi, and BeagleBone Black, also have native serial ports (i.e. non-USB, non-Bluetooth), and the people that use these types of devices are the very one which are extremely frustrated by the lack of support

Re: Intent to implement: Prerendering API

2014-08-12 Thread Andrew Sutherland
On 08/12/2014 04:04 PM, Ilya Grigorik wrote: In short, seems like this is inventing a derivative single-page app model for building pages/apps, and that makes me wonder because it doesn't seem to make it any easier. Everything described here can be achieved with current tools, but perhaps

Re: Moratorium on new XUL features

2014-10-13 Thread Andrew Sutherland
On 10/13/2014 07:06 PM, Joshua Cranmer  wrote: I nominally agree with this sentiment, but there are a few caveats: 1. nsITreeView and xul:tree exist and are usable in Mozilla code today. No HTML-based alternative to these are so easily usable. There are many lazy-rendering infinite

Sane/possible to implement/standardize opt-in (user and page) mobile show password behavior for HTML input type=password?

2014-12-12 Thread Andrew Sutherland
One of the UI polish issues that is facing Firefox OS apps is inclusion of a show password mechanism. Although the adoption of Web Components makes this something that can be addressed in a somewhat unified fashion, this seems like an affordance that is probably universally desired on (at

Re: Sane/possible to implement/standardize opt-in (user and page) mobile show password behavior for HTML input type=password?

2014-12-12 Thread Andrew Sutherland
On 12/12/2014 06:24 PM, Ehsan Akhgari wrote: On 2014-12-12 6:19 PM, Tanvi Vyas wrote: A touch event or mouseclick-and-hold on the eye icon could show the password, and as soon as the user releases the password can go back to being obfuscated. That would prevent accidental leakage through

Re: Evaluating the performance of new features

2015-02-01 Thread Andrew Sutherland
On Sun, Feb 1, 2015, at 11:13 PM, Jonas Sicking wrote: On Sun, Feb 1, 2015 at 3:28 AM, Kyle Huey m...@kylehuey.com wrote: Do we have actual evidence that indexeddb performance is a problem? I've never seen any. Yup. I think this is a very good question. Did the people writing

Re: IndexedDB transactions are no longer durable by default, and other changes

2015-04-01 Thread Andrew Sutherland
On Wed, Apr 1, 2015, at 05:12 PM, Andrew Sutherland wrote: On Wed, Apr 1, 2015, at 03:02 PM, ben turner (bent) wrote: If a crash or power loss occurs at just the right moment then the transaction will be lost/rolled back. It should still be impossible to ever see database corruption though

Re: May I execute mozIStorageStatement.executeAsync() at the same time in a single thread?

2015-04-24 Thread Andrew Sutherland
On 04/24/2015 12:48 PM, Yonggang Luo wrote: I am currently using executeAsync to do async sqlite operation in main thread, and running multiple executeAsync in parallel, and it's crashed, I am not so sure if multiple executeAsync can be executed at the same time. This is fine. The

Re: ES6 features (let, yield) and DOM workers and B2G

2015-04-29 Thread Andrew Sutherland
On 04/29/2015 03:10 PM, Jonas Sicking wrote: But has anyone reached out to the JS team and let them know that we really need let and yield in workers to see if A is an option? This is the reaching-out stage now* :). When I filed bug 1151739 the only impacted app was the email app, and that

Re: ES6 features (let, yield) and DOM workers and B2G

2015-04-29 Thread Andrew Sutherland
Update/data after talking with sfink/jorendorff/Waldo/shu of the JS team and some follow-up investigation with thanks to sfink to initiating the conversation: - yield inside function* is working fine inside a worker with JSVERSION_DEFAULT; we suspect the error I was relaying was not inside a

ES6 features (let, yield) and DOM workers and B2G

2015-04-29 Thread Andrew Sutherland
All content DOM workers use JSVERSION_DEFAULT unless the dom.workers.latestJSVersion pref is set to true. (Note: you need to manually add the pref in about:config.) Chrome workers get JSVERSION_LATEST. There is no way to tell the worker to use a specific JS version like we can do in page

Re: Changing the style guide's preference for loose over strict equality checks in non-test code

2015-05-14 Thread Andrew Sutherland
On 05/14/2015 04:22 PM, Gijs Kruitbosch wrote: == is not any less explicit than ===. Both versions have an exact, specified meaning. They both have exact meanings. But people, especially new contributors new to JS, frequently use == without understanding the nuances and footguns involved.

Re: IndexedDB transactions are no longer durable by default, and other changes

2015-04-01 Thread Andrew Sutherland
On Wed, Apr 1, 2015, at 03:02 PM, ben turner (bent) wrote: In the meantime, if the dom.indexedDB.experimental pref is set (defaults to |false| in Firefox and |true| in B2G, I think) I don't think it's set to true for B2G right now. I don't see such a mapping in

Re: Strange Error: Reentrancy error: some client, attempted to display a message to the console while in a console,listener

2015-07-01 Thread Andrew Sutherland
This is probably due to https://dxr.mozilla.org/comm-central/source/mailnews/test/resources/logHelper.js that registers itself as a console listener and its low-tech feedback loop prevention. (NB: The quippy file-level comment should be s/aweswome/Andrew/ for the third instance of awesome.) See

Re: How to avoid mozilla firefox remote debugger to ignore specific files

2015-08-22 Thread Andrew Sutherland
On 08/22/2015 10:57 AM, 罗勇刚(Yonggang Luo) wrote: I wanna to ignore some files when debugging . https://developer.mozilla.org/en-US/docs/Tools/Debugger/How_to/Black_box_a_source ___ dev-platform mailing list dev-platform@lists.mozilla.org

Web API equivalent of nsIEffectiveTLDService / publicsuffix.org database?

2015-08-08 Thread Andrew Sutherland
Are there any plans to surface the contents of https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIEffectiveTLDService from https://publicsuffix.org/ via a web-facing URI? Or is the long term expectation that web content will just embed the list in the app,

Re: Web API equivalent of nsIEffectiveTLDService / publicsuffix.org database?

2015-08-08 Thread Andrew Sutherland
On 08/08/2015 10:00 PM, Andrew Sutherland wrote: Are there any plans to surface the contents of https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIEffectiveTLDService from https://publicsuffix.org/ via a web-facing URI? And of course I meant API here. Most

Re: Switch to Google C++ Style Wholesale (was Re: Proposal to remove `aFoo` prescription from the Mozilla style guide for C and C++)

2015-07-15 Thread Andrew Sutherland
Would it be crazy for us to resort to a poll on these things? I propose abusing the mozillans.org skills field in profiles. For example, I have created the following sets of skills on mozillians.org by question, and which should autocomplete if you go to the edit page for your profile at

Re: Merging comm-central into mozilla-central

2015-10-23 Thread Andrew Sutherland
On Fri, Oct 23, 2015, at 01:02 PM, Joshua Cranmer  wrote: > Actually, the b2g email app does reuse JSMime (or at least will be > shortly). Clarifying: Yes, library reuse is happening and it's good and awesome and we want more of it. But: b2g gaia email does not now and is unlikely to ever care

Re: Intent to unship: ISO-2022-JP-2 support in the ISO-2022-JP decoder

2015-11-30 Thread Andrew Sutherland
On Mon, Nov 30, 2015, at 01:24 PM, Adam Roach wrote: > Does this mean it might interact with webmail services as well? Or do > they tend to do server-side transcoding from the received encoding to > something like UTF8? They do server-side decoding. It would take a tremendous amount of effort

Re: Service Worker - Offline fallback not working

2016-05-31 Thread Andrew Sutherland
"offline.html" does not appear to be in filesToCache that is passed to cache.addAll(). On Mon, May 30, 2016, at 03:02 PM, Mohit Bajoria wrote: > Hello > > There is offline.html page in repository. When there is no internet > connection then it should show up reading from cache. > Right now it

Re: Service Worker - Offline fallback not working

2016-05-31 Thread Andrew Sutherland
uot; doesn't show up. > > Github project link - > https://github.com/mbj36/My-Blog/commits/gh-pages > > Please help > Thanks > Mohit > > On 31 May 2016 at 23:45, Andrew Sutherland > <asutherl...@asutherland.org> wrote: >> "offline.html" does not ap

Gecko gdb pretty printers now understand nsTHashtable/friends

2016-07-18 Thread Andrew Sutherland
https://bugzilla.mozilla.org/show_bug.cgi?id=1286467 has landed, so if you have the following in your .gdbinit: add-auto-load-safe-path ~/some/parent/dir/of/where/you/keep/gecko You're now going to see stuff like the following for a hashtable with entries: mRegistrationInfos =

Re: DXR: How to encourage people to link to perma-links instead of plain ones?

2016-08-08 Thread Andrew Sutherland
On Mon, Aug 8, 2016, at 09:35 AM, Boris Zbarsky wrote: > When you click a link to a particular line in dxr, that would normally > navigate from https://dxr/foo to https://dxr/foo#lineno. Instead, have > it navigate to https://dxr/rev/foo#lineno. It would be great if DXR could expose a

Re: Doxygen output?

2017-02-21 Thread Andrew Sutherland
On Tue, Feb 21, 2017, at 03:13 PM, Bill McCloskey wrote: > I've been thinking about how to integrate documentation into Searchfox. > One > obvious thing is to allow it to display Markdown files and > reStructuredText. I wonder if it could do something useful with Doxygen > comments though? Is this

Re: Doxygen output?

2017-02-27 Thread Andrew Sutherland
On Tue, Feb 21, 2017, at 04:42 PM, Andrew Sutherland wrote: > A sketch first steps implementation would be: I took a shot at this. The pull request with details is at https://github.com/bill-mccloskey/searchfox/pull/11 and hopefully self-explanatory screenshots are here: ht

netwerk and media experts; feedback requests for background upload/download WebAPI video download use-case

2016-09-07 Thread Andrew Sutherland
There's a proposal at https://github.com/jakearchibald/background-cache for enabling persistently-tracked uploads/downloads in the background. It might change names to background-fetch. I'm interested in getting some informed feedback about the following use-case on

Would "Core :: Debugging: gdb" be a good bugzilla component?

2016-09-16 Thread Andrew Sutherland
Right now the gecko gdb pretty-printers have been tracked using bugs in "Core :: Build Config" because that's where the bug that first added them lived. That component currently has 1773 bugs in it, 3 of which involve gdb, and with daily activity of ~10 bugs a day. I think a more targeted

Re: Please do NOT hand-edit web platform test MANIFEST.json files

2017-03-18 Thread Andrew Sutherland
On Sun, Mar 19, 2017, at 12:36 AM, Nils Ohlmeier wrote: > Wouldn’t it make more sense to let the build system detect and > reject/warn about (?) such a manual modification? > My assumption here is that mailing list archives are not a good place to > document processes or systems. I think some

Re: Avoiding jank in async functions/promises?

2017-05-22 Thread Andrew Sutherland
On Sun, May 21, 2017, at 09:29 PM, Mark Hammond wrote: > As I mentioned at the start of the thread, in one concrete example we > had code already written that we identified being janky - >

Re: Shipping Headless Firefox on Linux

2017-06-15 Thread Andrew Sutherland
On Thu, Jun 15, 2017, at 03:27 AM, ishikawa wrote: > On local machine, when I added a modal error dailog as a response to an > error condition, which happens to be artificially created and tested in > xpcshell test, the test fails because the screen or whatever is not > available. Fair enough,

Re: Shipping Headless Firefox on Linux

2017-06-15 Thread Andrew Sutherland
On Thu, Jun 15, 2017, at 09:37 PM, ISHIKAWA,chiaki wrote: > Interesting. > But this covers only modal prompts generated by/in JavaScript modules, > and not C++ code? > If so, maybe I should re-think my previous error/warning dialog to see > if the generation can be moved to JavaScript code. > It

Changing remote type of xpcshell Content processes from "" to "web"

2017-09-01 Thread Andrew Sutherland
Right now if you have an e10s xpcshell test, the remote type of the resulting child (content) process will be NO_DEFAULT_TYPE="". This is not a real type, this is not a type you should ever see in Firefox. In https://bugzilla.mozilla.org/show_bug.cgi?id=1395827 I propose changing the type to

Intent to ship: navigator.storage on Firefox for Android (Fennec)

2018-06-20 Thread Andrew Sutherland
As of Firefox 63 we're hoping to turn navigator.storage (StorageManager[1]) on by default for Firefox for Android (Fennec).  It is controlled by pref "dom.storageManager.enabled" and provides both the storage.estimate() and storage.persist() API's[2]. We shipped navigator.storage for Desktop

Change to MOZ_LOG output formatting coming: Thread identifiers will include the PID (process id)

2018-01-10 Thread Andrew Sutherland
Right now MOZ_LOG's default output does not include process identifiers, so messages from different processes look misleadingly similar: [Main Thread]: D/nsBlah Message Message [Main Thread]: D/nsBlah Message Message They will soon instead look like: [4372:Main Thread]: D/nsBlah Message

Re: Intent to unship: "storage" attribute in options for indexedDB.open()

2018-03-06 Thread Andrew Sutherland
QuotaManager already has a notion of "internal" origins[1] that explicitly white-lists devtools' synthetic "indexeddb" fake scheme.  It's this check that avoids the prompt when persistent storage is requested. It might make sense to expand the existing logic that acts like all

Re: Help: why won't Thunderbird display mail in mochitest conditions?

2019-08-27 Thread Andrew Sutherland
Can you elaborate on the execution context?  Are these more like "browser" mochitests or "plain" mochitests? (https://developer.mozilla.org/en-US/docs/Mozilla/Projects/Mochitest#Running_flavors_and_subsuites) Is the Thunderbird tabbed UI its own normal XUL window self, or is it framed inside

Re: Coding style: Naming parameters in lambda expressions

2019-09-06 Thread Andrew Sutherland
On 9/6/19 7:31 AM, David Teller wrote: For what it's worth, I recently spent half a day attempting to solve a bug which would have been trivial if `a` and `m` prefixes had been present in that part of the code. While I find these notations ugly, they're also useful. Is this something

Re: Upcoming changes to hg.mozilla.org access

2019-11-01 Thread Andrew Sutherland
On 11/1/19 4:39 PM, Kim Moir wrote: On Nov 14, 2019, we intend to change the permissions associated with Level 3 access to revoke direct push access to hg.mozilla.org on mozilla-inbound, mozilla-central, mozilla-beta, mozilla-release and esr repos. For mozilla-beta, mozilla-release, and esr...

Re: New and improved stack-fixing

2020-03-05 Thread Andrew Sutherland
Does this eliminate the need documented at https://developer.mozilla.org/en-US/docs/Mozilla/Projects/Mochitest#stacks to acquire a `minidump_stackwalk` binary and then expose it via MINIDUMP_STACKWALK environment variable to get symbolicated backtraces when local test runs crash?  Or is that

Re: New and improved stack-fixing

2020-03-06 Thread Andrew Sutherland
On 3/6/20 2:24 AM, Gabriele Svelto wrote: Now for the long answer: we're leveraging the Sentry crates to replace our current crash reporting machinery. Not only they're faster and better than what we have now but their functionality is far richer. So it will be possible - and possibly even

Re: Searchfox at All-Hands: Who's interested?

2020-01-29 Thread Andrew Sutherland
by Thursday morning which should help you come up to speed pre-emptively or just-in-time if you miss the not-a-lecture at the beginning of the session. On 1/9/20 1:43 PM, Andrew Sutherland wrote: Are people interested in a session(s) at the All-Hands on Searchfox? If you're interested in any

Searchfox at All-Hands: Who's interested?

2020-01-11 Thread Andrew Sutherland
Are people interested in a session(s) at the All-Hands on Searchfox?  If you're interested in any of the following things, please email me here or at as...@mozilla.com or let me know via other channels, and let me know which of the following you'd be interested in.  My goal is to get a rough

Re: Visibility of disabled tests

2020-01-11 Thread Andrew Sutherland
On 1/8/20 12:50 PM, Geoffrey Brown wrote: Instead of changing the reviewers, how about:  - we remind the sheriffs to needinfo  - #intermittent-reviewers check that needinfo is in place when reviewing disabling patches. To try and help address the visibility issue, we could also make

Re: mach logspam

2020-08-03 Thread Andrew Sutherland
On 8/3/20 6:45 PM, Eric Rahm wrote: *What's next?* If folks want to improve the tool I'm happy to land patches in my repo, or if someone wants to support it officially in the mozilla repo I'm happy to transfer ownership. This is a most excellent tool! I wonder how hard it would be to get it

Searchfox now gives info about tests at the top of test files!

2020-07-28 Thread Andrew Sutherland
Have you ever been looking at a test file in Searchfox and wondered how the test could possibly work?  Then you do some more investigation and it turns out that the test, in fact, does not work and is disabled?  Perhaps you even melodramatically threw your hands up in the air in frustration?

Re: Searchfox now gives info about tests at the top of test files!

2020-07-29 Thread Andrew Sutherland
On 7/29/20 6:28 AM, James Graham wrote: As an aside/reminder for people, for web-platform-tests in particular the dashboard at https://jgraham.github.io/wptdash/ can give you information about all tests in a component and is designed to answer questions like "which tests are failing in Firefox