test(dbt): warn when DfE's LA averages fall behind the school results (review)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pipeline/transform/tests/assert_ks4_la_averages_current.sql

@@ -0,0 +1,20 @@
+{{ config(severity='warn') }}
+
+-- DfE's LA averages cover the latest year with school results. They come from
+-- a fixed EES data set (ks4_summary.KS4_SUMMARY_CSV_URL); when DfE publishes a
+-- new year under a new data set, the school results move on and this mart does
+-- not, so /api/la-averages serves an empty map and every "vs LA avg" goes.
+-- A warning, not an error: it must not hold back a new year's school results.
+
+with schools as (
+    select max(year) as year from {{ ref('stg_ees_ks4') }} where attainment_8_score is not null
+),
+
+las as (
+    select max(year) as year from {{ ref('fact_ks4_la_averages') }}
+)
+
+select s.year as latest_school_year, l.year as latest_la_year
+from schools s
+cross join las l
+where l.year is null or l.year < s.year