css/geometry/DOMMatrix-attributes.html

<!DOCTYPE html>
<title>Geometry Interfaces: DOMMatrix attributes</title>
<link rel="help" href="https://drafts.fxtf.org/geometry/#dommatrix-attributes">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
const initial = {
    a: 1, b: 0, c: 0, d: 1, e: 0, f: 0,
    m11: 1, m12: 0, m13: 0, m14: 0,
    m21: 0, m22: 1, m23: 0, m24: 0,
    m31: 0, m32: 0, m33: 1, m34: 0,
    m41: 0, m42: 0, m43: 0, m44: 1,
};

// Attributes that always preserve is2D.
["a", "b", "c", "d", "e", "f",
 "m11", "m12", "m21", "m22", "m41", "m42" ].forEach(attribute => {
    test(() => {
        let m = new DOMMatrix();
        assert_true(m.is2D);
        assert_equals(m[attribute], initial[attribute]);
        m[attribute] = 42;
        assert_true(m.is2D);
        assert_equals(m[attribute], 42);
    }, `DOMMatrix.${attribute}`);
});

// Attributes that clear is2D for values other than 0 or -0.
["m13", "m14", "m23", "m24", "m31", "m32", "m34", "m43" ].forEach(attribute => {
    test(() => {
        let m = new DOMMatrix();
        assert_true(m.is2D);
        assert_equals(m[attribute], initial[attribute]);
        m[attribute] = 0;
        assert_true(m.is2D, "0 preserves is2D");
        assert_equals(m[attribute], 0);
        m[attribute] = -0;
        assert_true(m.is2D, "-0 preserves is2D");
        assert_equals(m[attribute], -0);
        m[attribute] = 42;
        assert_false(m.is2D, "a value other than 0 or -0 clears is2D");
        assert_equals(m[attribute], 42);
        m[attribute] = 0;
        assert_false(m.is2D, "is2D can never be set to true after having been set to false");
        assert_equals(m[attribute], 0);
    }, `DOMMatrix.${attribute}`);
});

// Attributes that clear is2D for values other than 1.
["m33", "m44" ].forEach(attribute => {
    test(() => {
        let m = new DOMMatrix();
        assert_true(m.is2D);
        assert_equals(m[attribute], initial[attribute]);
        m[attribute] = 1;
        assert_true(m.is2D, "1 preserves is2D");
        assert_equals(m[attribute], 1);
        m[attribute] = 42;
        assert_false(m.is2D, "a value other than 1 clears is2D");
        assert_equals(m[attribute], 42);
        m[attribute] = 1;
        assert_false(m.is2D, "is2D can never be set to true after having been set to false");
        assert_equals(m[attribute], 1);
    }, `DOMMatrix.${attribute}`);
});
</script>