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'use strict';
function query_is_css_parseable(query) {
const style = document.createElement('style');
style.type = 'text/css';
document.head.appendChild(style);
const sheet = style.sheet;
try {
sheet.insertRule("@media " + query + "{}", 0);
return sheet.cssRules.length == 1 &&
sheet.cssRules[0].media.mediaText != "not all";
} finally {
while (sheet.cssRules.length)
sheet.deleteRule(0);
style.remove();
}
}
function query_should_be_css_parseable(query) {
test(() => {
assert_true(query_is_css_parseable(query));
}, "Should be parseable in a CSS stylesheet: '" + query + "'");
}
function query_should_not_be_css_parseable(query) {
test(() => {
assert_false(query_is_css_parseable(query));
}, "Should not be parseable in a CSS stylesheet: '" + query + "'");
}
function query_is_js_parseable(query) {
// We cannot rely on whether a given feature is on or off, so only check the
// 'media' member of the result.
const match = window.matchMedia(query);
return match.media == query;
}
function query_should_be_js_parseable(query) {
test(() => {
assert_true(query_is_js_parseable(query));
}, "Should be parseable in JS: '" + query + "'");
}
function query_should_not_be_js_parseable(query) {
test(() => {
assert_false(query_is_js_parseable(query));
}, "Should not be parseable in JS: '" + query + "'");
}
function query_is_known(query) {
return window.matchMedia(`${query}, not all and ${query}`).matches;
}
function query_is_unknown(query) {
return !window.matchMedia(`${query}, not all and ${query}`).matches;
}
function query_should_be_known(query) {
test(() => {
assert_true(query_is_js_parseable(query), "Can parse with JS");
assert_true(query_is_css_parseable(query), "Can parse with CSS");
assert_true(query_is_known(query));
}, "Should be known: '" + query + "'");
}
function query_should_be_unknown(query) {
test(() => {
assert_true(query_is_js_parseable(query), "Can parse with JS");
assert_true(query_is_css_parseable(query), "Can parse with CSS");
}, "Should be parseable: '" + query + "'");
test(() => {
assert_true(query_is_unknown(query));
}, "Should be unknown: '" + query + "'");
}