| 1 | | == Why layout tests search for results the way they do == |
| 2 | | |
| 3 | | Here are the results fallback order for chromium-mac (as of April, 2011): |
| 4 | | |
| 5 | | {{{ |
| 6 | | 'leopard': ['chromium-mac-leopard', 'chromium-mac-snowleopard', 'chromium-mac', 'chromium', |
| 7 | | 'mac-leopard', 'mac-snowleopard', 'mac'], |
| 8 | | 'snowleopard': ['chromium-mac-snowleopard', 'chromium-mac', 'chromium', |
| 9 | | 'mac-snowleopard', 'mac'], |
| 10 | | }}} |
| 11 | | |
| 12 | | A common question is why chromium-mac-snowleopard and mac-snowleopard are in the fallback list for leopard. |
| 13 | | |
| 14 | | Here's the logic behind the layout test paths: |
| 15 | | |
| 16 | | Assume you have three tests called foo, bar, and baz and suppose we're |
| 17 | | a couple of years ago, when Leopard was the most recent version of the |
| 18 | | Mac. The generic version of a platform always contains the "future" or |
| 19 | | "latest" version of the results. |
| 20 | | |
| 21 | | |
| 22 | | {{{ |
| 23 | | LayoutTests/platform/chromium-mac contains: |
| 24 | | foo-expected.txt r1.1 |
| 25 | | bar-expected.txt r.1.1 |
| 26 | | baz-expected.txt r.1.1 |
| 27 | | }}} |
| 28 | | |
| 29 | | Now Snow Leopard comes out, and foo produces different results. You |
| 30 | | want SL to find the new file, and the other two to find the old file. |
| 31 | | We put the new file in the "future" version, and move the older file |
| 32 | | into the directory matching the last platform that passed it: |
| 33 | | |
| 34 | | {{{ |
| 35 | | platform/chromium-mac: |
| 36 | | foo-expected.txt r1.2 |
| 37 | | bar-expected.txt r1.1 |
| 38 | | baz-expected.txt r1.1 |
| 39 | | platform/chromium-mac-leopard: |
| 40 | | foo-expected.txt r1.1 |
| 41 | | }}} |
| 42 | | |
| 43 | | SL only looks in the -mac dir, and Leopard looks in -mac-leopard, then -mac. |
| 44 | | Now Lion comes out, and bar changes, and foo changes again. We can |
| 45 | | leave the -leopard directory alone, and create a new -snowleopard |
| 46 | | directory, and only have to move the two failing tests there: |
| 47 | | |
| 48 | | {{{ |
| 49 | | platform/chromium-mac: |
| 50 | | foo-expected.txt r1.3 |
| 51 | | bar-expected.txt r1.2 |
| 52 | | baz-expected.txt r1.1 |
| 53 | | platform/chromium-mac-snowleopard: |
| 54 | | foo-expected.txt r1.2 |
| 55 | | bar-expected.txt r1.1 |
| 56 | | platform/chromium-mac-leopard: |
| 57 | | foo-expected.txt r1.1 |
| 58 | | }}} |
| 59 | | |
| 60 | | Lion only looks in -mac, SL looks in -mac-snowleopard, then -mac, and |
| 61 | | Leopard looks in -leopard, then -snowleopard, then -mac. |
| 62 | | If Leopard didn't look in the snowleopard directory, then we would |
| 63 | | have to copy versions of files more places every time a new release |
| 64 | | came out. This approach minimizes the amount of file shuffling we have |
| 65 | | to do, and keeps most of the files in platform/chromium-mac. But, it |
| 66 | | means that version X needs to look in every newer version in order to |
| 67 | | find the right files. |
| 68 | | |
| 69 | | Another way to think of it is that directory X-1 contains all and only |
| 70 | | the files that were different between versions X-1 and X, and then |
| 71 | | realize that this is, in a sense, associative (but not commutative). |
| 72 | | So, if you want to find the differences between Leopard (Lion-2) and |
| 73 | | Lion, you can look for delta(Lion-2, Lion-1) then delta(Lion-1, Lion) |
| 74 | | (but you can't reverse the order). |
| 75 | | |
| 76 | | Also, in Chromium we try to match the upstream baselines where |
| 77 | | possible (but we prioritize Chromium results over upstream results), |
| 78 | | so we look in both the chromium version-specific path and then the |
| 79 | | upstream version-specific path. |
| | 1 | This page is obsolete. See [wiki:LayoutTestSearchPath] instead. |
