test(sim): Phase 2 lockdown — guard BJT/diode model upgrades

Asserts the Phase 2 BJTs include Gummel-Poon junction caps (CJC/CJE)
and forward transit time (TF), and the diode upgrades include
reverse-recovery time (tt) and Schottky band-gap (Eg). If anyone
simplifies the models in the future, these regress fail and surface
the loss of AC/transient fidelity.

Also guards the dedupe identity between the canonical diode-1n4148
emission and the relay flyback diode — they must serialise as the same
string or ngspice will reject the netlist for duplicate .model lines.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/__tests__/phase-2-device-models.test.ts

@@ -0,0 +1,87 @@
+/**
+ * Phase 2 lockdown — verify the BJT and diode model upgrades survived
+ * any later edits to componentToSpice.ts. Asserts that the upgraded
+ * models include the parameters that distinguish them from the old
+ * truncated SPICE3F5 placeholders.
+ *
+ * If these fail, someone reasonably simplified the models again — that
+ * regresses AC/transient fidelity. Either re-upgrade the model or
+ * remove this test consciously.
+ */
+import { describe, it, expect } from 'vitest';
+import { componentToSpice } from '../simulation/spice/componentToSpice';
+import type { PlacedComponent } from '../simulation/spice/types';
+
+function netLookupStub(_pin: string): string {
+  return 'net_dummy';
+}
+
+function emit(metadataId: string, properties: Record<string, unknown> = {}): string[] {
+  const comp: PlacedComponent = { id: 't1', metadataId, properties };
+  const result = componentToSpice(comp, netLookupStub, { vcc: 5 });
+  if (!result) throw new Error(`no emission for ${metadataId}`);
+  return Array.from(result.modelsUsed);
+}
+
+describe('Phase 2 — BJT Gummel-Poon parameters present', () => {
+  it.each([
+    ['bjt-2n2222', 'Q2N2222'],
+    ['bjt-bc547', 'QBC547'],
+    ['bjt-2n3055', 'Q2N3055'],
+    ['bjt-2n3906', 'Q2N3906'],
+    ['bjt-bc557', 'QBC557'],
+  ])('%s model includes Gummel-Poon junction caps and transit times', (id, modelName) => {
+    const models = emit(id);
+    const m = models.find((s) => s.includes(modelName));
+    expect(m, `no model card found for ${modelName}`).toBeDefined();
+    const text = (m ?? '').toUpperCase();
+    // Junction caps — separates Phase 2 model from the old truncated one.
+    expect(text).toMatch(/CJC=/);
+    expect(text).toMatch(/CJE=/);
+    // Forward transit time — required for switching/AC behaviour.
+    expect(text).toMatch(/TF=/);
+    // Bf must still be there too (sanity).
+    expect(text).toMatch(/BF=/);
+  });
+});
+
+describe('Phase 2 — diode reverse-recovery and junction capacitance', () => {
+  it('D1N4148 includes tt (storage time) and Cjo', () => {
+    const models = emit('diode-1n4148');
+    const m = models.find((s) => s.includes('D1N4148'));
+    expect(m).toBeDefined();
+    expect(m).toMatch(/tt=/i);
+    expect(m).toMatch(/Cjo=/i);
+  });
+
+  it('Schottky 1N5817 carries Eg (Schottky band-gap) and Cjo', () => {
+    const models = emit('diode-1n5817');
+    const m = models.find((s) => s.includes('D1N5817'));
+    expect(m).toBeDefined();
+    expect(m).toMatch(/Eg=/i);
+    expect(m).toMatch(/Cjo=/i);
+  });
+
+  it('Schottky 1N5819 carries Eg and Cjo', () => {
+    const models = emit('diode-1n5819');
+    const m = models.find((s) => s.includes('D1N5819'));
+    expect(m).toBeDefined();
+    expect(m).toMatch(/Eg=/i);
+    expect(m).toMatch(/Cjo=/i);
+  });
+});
+
+describe('Phase 2 — relay flyback keeps the canonical D1N4148 string', () => {
+  it('relay emits the same D1N4148 .model string as a standalone diode', () => {
+    const standaloneModels = emit('diode-1n4148');
+    const relayModels = emit('relay');
+    const standalone = standaloneModels.find((s) => s.includes('D1N4148'));
+    const fromRelay = relayModels.find((s) => s.includes('D1N4148'));
+    expect(standalone).toBeDefined();
+    expect(fromRelay).toBeDefined();
+    // Must match exactly — the netlist dedupe Set collapses them by string
+    // identity. If they ever diverge, ngspice will see duplicate .model
+    // definitions and error out.
+    expect(fromRelay).toBe(standalone);
+  });
+});