This is a testharness.js-based test.
FAIL Constructing a CSSVariableReferenceValue with an invalid variable name throws SyntaxError assert_throws: function "() => new CSSVariableReferenceValue('bar')" did not throw
FAIL Updating CSSVariableReferenceValue.variable to an invalid variable name throws SyntaxError assert_throws: function "() => result.variable = 'bar'" did not throw
PASS CSSVariableReferenceValue can be constructed with no fallback
PASS CSSVariableReferenceValue can be constructed with fallback
PASS CSSVariableReferenceValue.variable can updated to a valid variable name
PASS CSSVariableReferenceValue.fallback can updated to null
PASS CSSVariableReferenceValue.fallback can updated to a CSSUnparsedValue
Harness: the test ran to completion.