testing period
(8) Increase in limit for individuals becoming eligible individuals after the beginning of the year (A) In general For purposes of computing the limitation under paragraph (1) for any taxable year, an individual who is an eligible individual during the last month of such taxable year shall be treated— (i) as having been an eligible individual during each of the months in such taxable year, and (ii) as having been enrolled, during each of the months such individual is treated as an eligible individual solely by reason of clause (i), in the same high deductible health plan in which the individual was enrolled for the last month of such taxable year. (B) Failure to maintain high deductible health plan coverage (i) In general If, at any time during the testing period, the individual is not an eligible individual, then— (I) gross income of the individual for the taxable year in which occurs the first month in the testing period for which such individual is not an eligible individual is increased by the aggregate amount of all contributions to the health savings account of the individual which could not have been made but for subparagraph (A), and (II) the tax imposed by this chapter for any taxable year on the individual shall be increased by 10 percent of the amount of such increase. (ii) Exception for disability or death Subclauses (I) and (II) of clause (i) shall not apply if the individual ceased to be an eligible individual by reason of the death of the individual or the individual becoming disabled (within the meaning of section 72(m)(7) ). (iii) Testing period The term “testing period” means the period beginning with the last month of the taxable year referred to in subparagraph (A) and ending on the last day of the 12th month following such month.
Source
26 USC § 223(b)(8)
Scoping language
None identified, default scope is assumed to be the parent (part VII) of this section.