| # Test Assumptions |
| |
| The tests make a number of assumptions of the user agent, and new |
| tests can freely rely on these assumptions being true: |
| |
| * The device is a full-color device. |
| * The device has a viewport width of at least 800px. |
| * The UA imposes no minimum font size. |
| * The `medium` `font-size` computes to 16px. |
| * The canvas background is `white`. |
| * The initial value of `color` is `black`. |
| * The user stylesheet is empty (except where indicated by the tests). |
| * The device is interactive and uses scroll bars. |
| * The HTML `div` element is assigned `display: block;`, the |
| `unicode-bidi` property may be declared, and no other property |
| declarations. |
| <!-- unicode-bidi: isolate should be required; we currently don't |
| assume this because Chrome and Safari are yet to ship this: see |
| https://bugs.chromium.org/p/chromium/issues/detail?id=296863 and |
| https://bugs.webkit.org/show_bug.cgi?id=65617 --> |
| * The HTML `span` element is assigned `display: inline;` and no other |
| property declaration. |
| * The HTML `p` element is assigned `display: block;` |
| * The HTML `li` element is assigned `display: list-item;` |
| * The HTML `table` elements `table`, `tbody`, `tr`, and `td` are |
| assigned the `display` values `table`, `table-row-group`, |
| `table-row`, and `table-cell`, respectively. |
| * The UA implements reasonable line-breaking behavior; e.g., it is |
| assumed that spaces between alphanumeric characters provide line |
| breaking opportunities and that UAs will not break at every |
| opportunity, but only near the end of a line unless a line break is |
| forced. |
| |
| Tests for printing behavior make some further assumptions: |
| |
| * The UA is set to print background colors and, if it supports |
| graphics, background images. |
| * The UA implements reasonable page-breaking behavior; e.g., it is |
| assumed that UAs will not break at every opportunity, but only near |
| the end of a page unless a page break is forced. |
