| PASS | Converting a CSSNumericValue to a sum with invalid units throws SyntaxError | |
| PASS | Converting a CSSNumericValue with an invalid sum value to a sum throws TypeError | |
| PASS | Converting a CSSNumericValue with compound units to a sum throws TypeError | |
| PASS | Converting a CSSNumericValue to a sum with an incompatible unit throws TypeError | |
| PASS | Converting a CSSNumericValue to a sum with units that are not addable throws TypeError | |
| PASS | Converting a CSSNumericValue with leftover units to a sum throws TypeError | |
| PASS | Converting CSSNumericValue to a sum with its own unit returns itself | |
| PASS | Converting CSSNumericValue to a sum with no arguments returns all the units in sorted order | |
| PASS | Converting CSSNumericValue to a sum with a relative unit converts correctly | |
| PASS | Converting CSSNumericValue to a sum containing extra units returns zero for those units | |
| PASS | CSSNumericValue.toSum converts greedily | |