feat(sprint1-step3): PrestigePanel + MilestoneBar + équilibrage générateurs fixes

Frontend/src/__tests__/economy.test.ts

@@ -11,6 +11,50 @@ import {
   DEFAULT_GENERATORS,
 } from "../core/economy";
 
+// PrestigePanel visibility guard — canPrestige drives render condition
+// Ces tests valident l'invariant : le panneau prestige ne doit jamais être
+// visible (canPrestige = false) si les ressources sont inférieures au seuil.
+describe("PrestigePanel visibility (canPrestige guard)", () => {
+  it("canPrestige = false pour resources = 0 → panneau non visible", () => {
+    expect(canPrestige({ ...DEFAULT_STATE, resources: 0 })).toBe(false);
+  });
+
+  it("canPrestige = false pour resources = 999 999 → panneau non visible", () => {
+    expect(canPrestige({ ...DEFAULT_STATE, resources: 999_999 })).toBe(false);
+  });
+
+  it("canPrestige = true pour resources = 1 000 000 → panneau visible", () => {
+    expect(canPrestige({ ...DEFAULT_STATE, resources: 1_000_000 })).toBe(true);
+  });
+});
+
+describe("applyPrestige — post-prestige state", () => {
+  const prestigeState = {
+    ...DEFAULT_STATE,
+    resources: 1_500_000,
+    generators: DEFAULT_STATE.generators.map((g) => ({ ...g, owned: 3 })),
+    prestigeCount: 0,
+    prestigeMultiplier: 1,
+  };
+
+  it("ressources = 0 après prestige", () => {
+    expect(applyPrestige(prestigeState).resources).toBe(0);
+  });
+
+  it("multiplicateur = 1.1 après premier prestige", () => {
+    expect(applyPrestige(prestigeState).prestigeMultiplier).toBeCloseTo(1.1);
+  });
+
+  it("tous les générateurs owned = 0 après prestige", () => {
+    const result = applyPrestige(prestigeState);
+    expect(result.generators.every((g) => g.owned === 0)).toBe(true);
+  });
+
+  it("prestigeCount incrémenté à 1 après premier prestige", () => {
+    expect(applyPrestige(prestigeState).prestigeCount).toBe(1);
+  });
+});
+
 describe("generatorCost", () => {
   it("retourne baseCost quand owned = 0", () => {
     const gen = { ...DEFAULT_GENERATORS[0], owned: 0 };