diff --git a/src/features/charts/PriceHistoryChart.tsx b/src/features/charts/PriceHistoryChart.tsx
index 7ed3408e..e64ee42c 100644
--- a/src/features/charts/PriceHistoryChart.tsx
+++ b/src/features/charts/PriceHistoryChart.tsx
@@ -1,4 +1,4 @@
-// src/components/PriceHistoryChart.tsx
+// src/features/charts/PriceHistoryChart.tsx
 import React, { useState, useEffect, useMemo } from 'react';
 import {
   LineChart,
@@ -198,7 +198,12 @@ export const PriceHistoryChart: React.FC = () => {
               borderRadius: '0.5rem',
             }}
             labelStyle={{ color: '#F9FAFB' }}
-            formatter={(value: number) => `$${(value / 100).toFixed(2)}`}
+            formatter={(value: number | undefined) => {
+              if (typeof value === 'number') {
+                return [`$${(value / 100).toFixed(2)}`];
+              }
+              return [null];
+            }}
           />
           <Legend wrapperStyle={{ fontSize: '12px' }} />
           {availableItems.map((item, index) => (
diff --git a/src/hooks/useUserData.test.tsx.disabled b/src/hooks/useUserData.test.tsx
similarity index 100%
rename from src/hooks/useUserData.test.tsx.disabled
rename to src/hooks/useUserData.test.tsx
diff --git a/src/routes/system.routes.test.ts.disabled b/src/routes/system.routes.test.ts
similarity index 100%
rename from src/routes/system.routes.test.ts.disabled
rename to src/routes/system.routes.test.ts