feat(compare): trends explorer with England line; gap-honest axis; series regression guard

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0146VHeLAWjDVE2B5uU67jCB
2026-07-13 23:54:58 +01:00
parent 2573cd2490
commit 519584f34b
6 changed files with 523 additions and 16 deletions
@@ -0,0 +1,84 @@
+/**
+ * buildCompareChart: every selected school must produce a rendered series
+ * (regression guard for the production bug where a third school's line
+ * vanished), the x-axis must include cancelled/unpublished years as real
+ * gaps (never compressing time), and the England overlay renders dashed
+ * with no gap-bridging.
+ */
+
+import { buildCompareChart, fillAcademicYears } from '@/lib/compareChartData';
+import type { ComparisonData } from '@/lib/types';
+
+function school(urn: number, years: Array<[number, number | null]>): ComparisonData {
+  return {
+    school_info: { urn, school_name: `School ${urn}` } as ComparisonData['school_info'],
+    yearly_data: years.map(([year, v]) => ({ year, rwm_expected_pct: v })) as ComparisonData['yearly_data'],
+  };
+}
+
+const THREE_SCHOOLS = {
+  '1': school(1, [[201819, 87], [202223, 87], [202425, 87]]),
+  '2': school(2, [[201819, 88], [202223, 88], [202425, 92]]),
+  '3': school(3, [[201819, 69], [202223, 62], [202425, 79]]),
+};
+
+const SCHOOL_LIST = [1, 2, 3].map((urn) => ({ urn, school_name: `School ${urn}` }));
+
+describe('fillAcademicYears', () => {
+  it('fills every academic year between min and max', () => {
+    expect(fillAcademicYears([201819, 202223])).toEqual([
+      201819, 201920, 202021, 202122, 202223,
+    ]);
+  });
+});
+
+describe('buildCompareChart', () => {
+  it('renders one series per selected school — none silently dropped', () => {
+    const chart = buildCompareChart(THREE_SCHOOLS, SCHOOL_LIST, 'rwm_expected_pct');
+    expect(chart.schoolDatasets).toHaveLength(3);
+    for (const ds of chart.schoolDatasets) {
+      expect(ds.data.some((v) => v != null)).toBe(true);
+    }
+  });
+
+  it('handles float years from the API (202425.0 style)', () => {
+    const floaty = {
+      '1': school(1, [[201819.0 as number, 80], [202425.0 as number, 85]]),
+    };
+    const chart = buildCompareChart(floaty, [SCHOOL_LIST[0]], 'rwm_expected_pct');
+    expect(chart.schoolDatasets[0].data.filter((v) => v != null)).toHaveLength(2);
+  });
+
+  it('includes cancelled/unpublished years as null gaps, not compressed time', () => {
+    const chart = buildCompareChart(THREE_SCHOOLS, SCHOOL_LIST, 'rwm_expected_pct');
+    expect(chart.years).toContain(201920);
+    expect(chart.years).toContain(202122);
+    const idx = chart.years.indexOf(202021);
+    expect(chart.schoolDatasets[0].data[idx]).toBeNull();
+  });
+
+  it('adds a dashed England overlay when national data is supplied', () => {
+    const chart = buildCompareChart(THREE_SCHOOLS, SCHOOL_LIST, 'rwm_expected_pct', {
+      201819: 64.9,
+      202122: 58.7,
+      202223: 59.5,
+      202425: 62.1,
+    });
+    expect(chart.englandDataset).not.toBeNull();
+    const eng = chart.englandDataset!;
+    expect(eng.label).toBe('England average');
+    expect(eng.borderDash).toEqual([5, 4]);
+    expect(eng.spanGaps).toBe(false);
+    // England has a value for 2021/22 even though schools do not
+    expect(eng.data[chart.years.indexOf(202122)]).toBe(58.7);
+  });
+
+  it('flags the unpublished 2021/22 school-level year when England has data but schools do not', () => {
+    const withNational = buildCompareChart(THREE_SCHOOLS, SCHOOL_LIST, 'rwm_expected_pct', {
+      202122: 58.7,
+    });
+    expect(withNational.showUnpublished202122Note).toBe(true);
+    const withoutNational = buildCompareChart(THREE_SCHOOLS, SCHOOL_LIST, 'rwm_expected_pct');
+    expect(withoutNational.showUnpublished202122Note).toBe(false);
+  });
+});