diff --git a/src/server/server.test.ts b/src/server/server.test.ts
index d169f95..8ef22bf 100644
--- a/src/server/server.test.ts
+++ b/src/server/server.test.ts
@@ -5,6 +5,10 @@ jest.mock('../utils/addition', () => ({
   addition: jest.fn((value: number) => value + 1)
 }));
 
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
 describe('server', () => {
   it('returns input value increased by one', async () => {
     const value = 1;
diff --git a/src/utils/addition.test.ts b/src/utils/addition.test.ts
index 22216d3..dfbfc4b 100644
--- a/src/utils/addition.test.ts
+++ b/src/utils/addition.test.ts
@@ -9,6 +9,10 @@ jest.mock('../database/database', () => ({
   }))
 }));
 
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
 describe('call', () => {
   it('returns the input value increased by one', async () => {
     const response = await addition(3);