[MaxGhenis]

Follows #408, which added companion cases to the same file and merged on 2026-10-01. This PR now targets main.

Adds 7 companion cases to uk/regulations/uksi/2013/376/schedule/4/paragraph/10.test.yaml. They pin the para 10 counts for other families' children, foster children, children placed for adoption and the para 12 additional bedrooms. The cases follow PolicyEngine/policyengine-uk#2011 and its fix PR PolicyEngine/policyengine-uk#2016, as read on 2026-10-01; PolicyEngine's current output was not re-run for this PR. No module bytes change.

Case	Allotted (non-dependants not children, under-10 pairs, same-sex pairs, other children; para 12)	Expected bedrooms
renter, son 12, a non-dependant daughter and her daughter 11	1, 0, 0, 2; 0	1 (a) + 1 (c) + 2 (f) = 4
renter, son 12, a non-dependant daughter and her son 8, who shares with the son	1, 0, 2, 0; 0	1 + 1 + 1 (e) = 3
renter, a non-dependant daughter and her two children under 10	1, 2, 0, 0; 0	1 + 1 + 1 (d) = 3
foster parent with two foster children, who are not in the extended benefit unit	0, 0, 0, 0; 1	1 + 1 = 2
couple, their son 5 and a foster daughter 3	0, 0, 0, 1; 1	1 + 1 (f) + 1 = 3
adopter with a child placed for adoption	0, 0, 0, 1; 1	1 + 1 + 1 = 3
foster couple, one with overnight care, two foster children	0, 0, 0, 0; 2	1 + 2 = 3

Law (legislation.gov.uk, fetched 2026-10-01):

• Para 10(1): "A renter is entitled to one bedroom for each of the following categories of persons in their extended benefit unit— (a) the renter (or joint renters); (b) a qualifying young person for whom the renter or either joint renter is responsible; (c) a non-dependant who is not a child; (d) two children who are under 10 years old; (e) two children of the same sex; (f) any other child."
• Para 10(2) allots each person to whichever description gives the fewest bedrooms.
• Para 10(3)(b) adds "any entitlement to an additional bedroom in accordance with paragraph 12".

Where the expected values come from. They are hand-computed from paras 9, 10 and 12. The cases were written to mirror PolicyEngine-UK's LHA_other_families_children_and_additional_bedrooms.yaml in PolicyEngine/policyengine-uk#2016 as it stood on 2026-10-01; exact equality with that fixture's current revision was not re-checked. An independent review recomputed each expected value from Schedule 4 paragraphs 10 and 12 at the test period.

• A non-dependant's own child is a non-dependant (para 9(2)(g), reg 4(2)), so counts under 10(1)(d)-(f) and shares with the renter's children. DWP guidance: "children of the main claimant or claimants with those of non-dependants" (Housing Costs Contributions – non-dependants, V13.0).
• A foster child is outside the extended benefit unit (para 9(2)(c), 9(3); reg 4(6)(a)).
• A child placed for adoption is the adopter's responsibility (reg 4A(1)(c), from 1 April 2024) and also gives the para 12(4)(b) bedroom.
• Para 12(9) gives one bedroom per condition (ADM F3138 examples 1 and 2).

Verification.

• axiom-encode test at the CI pins (axiom-encode c326d1ac, axiom-rules-engine 05eac9d2): "RuleSpec companion tests passed: 1 file(s), 12 case(s)" (5 already on main + 7 new).
• Changing one expectation (the last case to 4) fails with "expected 4, got … '3'".

Scope. Test-only, on the #350/#391/#408 pattern. For the PolicyEngine parity rule it closes UC Sch 4 para 10(1)(d)-(f) and (3)(b) for these cases as encoded-correct. Still open:

• Para 9 membership: a non-dependant's child is a non-dependant; a foster child is excluded under (c) and (g). This is step 1 of Encode the payer side for sharers, boarders and lodgers: UC Sch 4 paras 9 and 20, HB regs 3, 12B, 13D, 74 and Sch 1 meals, CTR joint liability (PE parity: policyengine-uk#2006) #406; see the addendum comment there.
• Para 12 and para 29: the additional bedroom count and the shared accommodation exceptions are inputs here. They are queued in Encode UC Sch 4 para 12 (additional bedroom) and para 29 (excepted persons) (PE parity: policyengine-uk#2011) #411.
• HB reg 13D: occupiers' children, reg 21(3) placements, and (3A)-(3B). Queued on Encode the payer side for sharers, boarders and lodgers: UC Sch 4 paras 9 and 20, HB regs 3, 12B, 13D, 74 and Sch 1 meals, CTR joint liability (PE parity: policyengine-uk#2006) #406 and Encode HB Regs 2006 regs 2, 19, 13D and 75CA (family definitions, young individual, benefit cap); replace the HB pipeline's supplied family status #357.

🤖 Generated with Claude Code

[MaxGhenis]

Merged by the Axiom engineering hub (session local_2d82123f) at b4a42ce with --merge. Gates: gh pr checks exit 0; MERGEABLE; not draft. Reviewed head: cf7276d; the merged head differs only by a base update, and the PR's own changed lines are identical to the reviewed head's. Hub adoption (quiet owner). Independent GPT-6.1 Sol review APPROVE_WITH_NITS at cf7276d (Subfleet 20261010-082724): each expected value recomputed from UC Regs 2013 Sch 4 paras 10 and 12; test-only, no module bytes change. Nits applied to the PR body (upstream PolicyEngine claims qualified). Main merged in to run the required validate check for the first time.