diff --git a/tests/helpers/EffectHelper.test.ts b/tests/helpers/EffectHelper.test.ts
index d9520a2..9e3b5b0 100644
--- a/tests/helpers/EffectHelper.test.ts
+++ b/tests/helpers/EffectHelper.test.ts
@@ -1,8 +1,33 @@
+import UserEffect from "../../src/database/entities/app/UserEffect";
+import EffectHelper from "../../src/helpers/EffectHelper";
+
 describe("AddEffectToUserInventory", () => {
     describe("GIVEN effect is in database", () => {
-        test.todo("EXPECT effect to be updated");
+        const effectMock = {
+            AddUnused: jest.fn(),
+            Save: jest.fn(),
+        };
 
-        test.todo("EXPECT effect to be saved");
+        beforeAll(async () => {
+            UserEffect.FetchOneByUserIdAndName = jest.fn().mockResolvedValue(effectMock);
+
+            await EffectHelper.AddEffectToUserInventory("userId", "name", 1);
+        });
+
+        test("EXPECT database to be fetched", () => {
+            expect(UserEffect.FetchOneByUserIdAndName).toHaveBeenCalledTimes(1);
+            expect(UserEffect.FetchOneByUserIdAndName).toHaveBeenCalledWith("userId", "name");
+        });
+
+        test("EXPECT effect to be updated", () => {
+            expect(effectMock.AddUnused).toHaveBeenCalledTimes(1);
+            expect(effectMock.AddUnused).toHaveBeenCalledWith(1);
+        });
+
+        test("EXPECT effect to be saved", () => {
+            expect(effectMock.Save).toHaveBeenCalledTimes(1);
+            expect(effectMock.Save).toHaveBeenCalledWith(UserEffect, effectMock);
+        });
     });
 
     describe("GIVEN effect is not in database", () => {