This is a testharness.js-based test.
[FAIL] CSSSupportsConditionRule interface: existence and properties of interface object
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface object length
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface object name
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface: existence and properties of interface prototype object
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface: existence and properties of interface prototype object's "constructor" property
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface: existence and properties of interface prototype object's @@unscopables property
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
[FAIL] CSSSupportsConditionRule interface: attribute name
  assert_own_property: self does not have own property "CSSSupportsConditionRule" expected property "CSSSupportsConditionRule" missing
Harness: the test ran to completion.