diff --git a/app/index.tsx b/app/index.tsx
index b88823e..bed4639 100644
--- a/app/index.tsx
+++ b/app/index.tsx
@@ -78,7 +78,7 @@ const IndexScreen: React.FC = () => {
       const loadedState = await loadState(slot);
       if (loadedState) {
         setPlayerCount(loadedState.playerCount);
-        setBuyInAmount(loadedState.buyInAmount);
+        setBuyInAmount(loadedState.buyInAmount ?? 20);
         setNumberOfChips(loadedState.numberOfChips);
         setTotalChipsCount(loadedState.totalChipsCount);
         setSelectedCurrency(loadedState.selectedCurrency || "$");
diff --git a/components/__tests__/BuyInSelector.test.tsx b/components/__tests__/BuyInSelector.test.tsx
index b20d528..ce29dbf 100644
--- a/components/__tests__/BuyInSelector.test.tsx
+++ b/components/__tests__/BuyInSelector.test.tsx
@@ -2,6 +2,7 @@ import React from "react";
 import { fireEvent, render } from "@testing-library/react-native";
 import BuyInSelector from "@/components/BuyInSelector";
 
+// Mocking vector icons to prevent errors
 jest.mock("@expo/vector-icons", () => {
   const { Text } = require("react-native");
   return {
@@ -10,63 +11,73 @@ jest.mock("@expo/vector-icons", () => {
 });
 
 describe("BuyInSelector Component", () => {
-  let setBuyInAmount;
-  let getByText;
-  let getByPlaceholderText;
-  let queryByText;
+  let setBuyInAmount: jest.Mock;
 
-  // Render the component with the necessary props
+  // Render the component and return query methods
   const renderComponent = (selectedCurrency = "$") => {
-    const result = render(
+    const utils = render(
       <BuyInSelector
         setBuyInAmount={setBuyInAmount}
         selectedCurrency={selectedCurrency}
       />
     );
-    getByText = result.getByText;
-    getByPlaceholderText = result.getByPlaceholderText;
-    queryByText = result.queryByText;
+    return {
+      ...utils,
+      getByText: utils.getByText,
+      getByPlaceholderText: utils.getByPlaceholderText,
+      queryByText: utils.queryByText,
+    };
   };
 
   beforeEach(() => {
     setBuyInAmount = jest.fn();
-    renderComponent();
   });
 
   it("renders the buy-in options and input correctly", () => {
+    const { getByText, getByPlaceholderText, queryByText } = renderComponent();
+
     expect(getByText("$ 10")).toBeTruthy();
     expect(getByText("$ 25")).toBeTruthy();
     expect(getByText("$ 50")).toBeTruthy();
     expect(getByPlaceholderText("Enter custom buy-in")).toBeTruthy();
-
-    // Check default selection with a more flexible approach
-    expect(queryByText(/Selected Buy-in.*None/)).toBeTruthy();
+    expect(queryByText(/Selected Buy-in:.*None/i)).toBeTruthy();
   });
 
   it("sets a predefined buy-in amount correctly", () => {
+    const { getByText } = renderComponent();
+
     fireEvent.press(getByText("$ 25"));
     expect(setBuyInAmount).toHaveBeenCalledWith(25);
   });
 
   it("sets a custom buy-in amount correctly", () => {
+    const { getByPlaceholderText } = renderComponent();
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "100");
     expect(setBuyInAmount).toHaveBeenCalledWith(100);
   });
 
   it("resets custom amount if invalid input is entered", () => {
+    const { getByPlaceholderText } = renderComponent();
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "-10");
-    expect(setBuyInAmount).toHaveBeenCalledWith(25);
+    expect(setBuyInAmount).toHaveBeenCalledWith(25); // Default reset
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "abc");
     expect(setBuyInAmount).toHaveBeenCalledWith(25);
   });
 
   it("clears the custom amount when selecting a predefined option", () => {
+    const { getByPlaceholderText, getByText } = renderComponent();
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "100");
     fireEvent.press(getByText("$ 50"));
     expect(setBuyInAmount).toHaveBeenCalledWith(50);
   });
 
   it("handles valid and invalid input for custom amount correctly", () => {
+    const { getByPlaceholderText } = renderComponent();
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "75");
     expect(setBuyInAmount).toHaveBeenCalledWith(75);
 
@@ -78,33 +89,40 @@ describe("BuyInSelector Component", () => {
   });
 
   it("triggers state update every time a buy-in option is clicked, even if it's the same", () => {
+    const { getByText } = renderComponent();
+
     fireEvent.press(getByText("$ 25"));
     fireEvent.press(getByText("$ 25"));
     expect(setBuyInAmount).toHaveBeenCalledTimes(2);
   });
 
   it("resets to default buy-in when custom input is cleared", () => {
+    const { getByPlaceholderText } = renderComponent();
     const input = getByPlaceholderText("Enter custom buy-in");
+
     fireEvent.changeText(input, "75");
     expect(setBuyInAmount).toHaveBeenCalledWith(75);
+
     fireEvent.changeText(input, "");
     expect(setBuyInAmount).toHaveBeenCalledWith(25);
   });
 
   it("updates state correctly when selecting predefined buy-in after entering a custom amount", () => {
+    const { getByPlaceholderText, getByText } = renderComponent();
+
     fireEvent.changeText(getByPlaceholderText("Enter custom buy-in"), "200");
     expect(setBuyInAmount).toHaveBeenCalledWith(200);
+
     fireEvent.press(getByText("$ 10"));
     expect(setBuyInAmount).toHaveBeenCalledWith(10);
   });
 
   it("displays selected currency correctly", () => {
-    renderComponent("€");
+    const { getByText, queryByText } = renderComponent("€");
+
     expect(getByText("€ 10")).toBeTruthy();
     expect(getByText("€ 25")).toBeTruthy();
     expect(getByText("€ 50")).toBeTruthy();
-
-    // Check default selection text with a flexible regex
-    expect(queryByText(/Selected Buy-in.*None/)).toBeTruthy();
+    expect(queryByText(/Selected Buy-in:.*None/i)).toBeTruthy();
   });
 });
diff --git a/components/__tests__/ChipDetection.test.tsx b/components/__tests__/ChipDetection.test.tsx
index 45ecb5e..2dac26c 100644
--- a/components/__tests__/ChipDetection.test.tsx
+++ b/components/__tests__/ChipDetection.test.tsx
@@ -17,11 +17,10 @@ jest.mock("expo-image-picker", () => ({
 describe("ChipDetection", () => {
   beforeEach(() => {
     jest.clearAllMocks();
-    global.fetch = jest.fn(() =>
-      Promise.resolve({
-        ok: true,
-        json: () =>
-          Promise.resolve({
+    jest.spyOn(global, "fetch").mockImplementation(() =>
+      Promise.resolve(
+        new Response(
+          JSON.stringify({
             choices: [
               {
                 message: {
@@ -34,10 +33,16 @@ describe("ChipDetection", () => {
               },
             ],
           }),
-      })
+          { status: 200, headers: { "Content-Type": "application/json" } }
+        )
+      )
     );
   });
 
+  afterEach(() => {
+    jest.restoreAllMocks(); // Reset all mocks to prevent test contamination
+  });
+
   it("renders correctly", () => {
     const { getByText } = render(
       <ChipDetection updateChipCount={mockUpdateChipCount} />
@@ -48,7 +53,7 @@ describe("ChipDetection", () => {
   });
 
   it("picks an image from the library", async () => {
-    ImagePicker.launchImageLibraryAsync.mockResolvedValueOnce({
+    (ImagePicker.launchImageLibraryAsync as jest.Mock).mockResolvedValueOnce({
       canceled: false,
       assets: [{ uri: "test-uri", base64: "test-base64" }],
     });
@@ -62,10 +67,12 @@ describe("ChipDetection", () => {
   });
 
   it("takes a photo with the camera", async () => {
-    ImagePicker.requestCameraPermissionsAsync.mockResolvedValueOnce({
+    (
+      ImagePicker.requestCameraPermissionsAsync as jest.Mock
+    ).mockResolvedValueOnce({
       granted: true,
     });
-    ImagePicker.launchCameraAsync.mockResolvedValueOnce({
+    (ImagePicker.launchCameraAsync as jest.Mock).mockResolvedValueOnce({
       canceled: false,
       assets: [{ uri: "test-camera-uri", base64: "test-camera-base64" }],
     });
@@ -81,7 +88,9 @@ describe("ChipDetection", () => {
   });
 
   it("handles camera permission denied", async () => {
-    ImagePicker.requestCameraPermissionsAsync.mockResolvedValueOnce({
+    (
+      ImagePicker.requestCameraPermissionsAsync as jest.Mock
+    ).mockResolvedValueOnce({
       granted: false,
     });
 
@@ -98,16 +107,18 @@ describe("ChipDetection", () => {
   });
 
   it("displays error message on image processing failure", async () => {
-    ImagePicker.launchImageLibraryAsync.mockResolvedValueOnce({
+    (ImagePicker.launchImageLibraryAsync as jest.Mock).mockResolvedValueOnce({
       canceled: false,
       assets: [{ uri: "test-uri", base64: "test-base64" }],
     });
 
-    global.fetch.mockImplementationOnce(() =>
-      Promise.resolve({
-        ok: false,
-        json: () => Promise.resolve({ choices: [] }),
-      })
+    jest.spyOn(global, "fetch").mockImplementationOnce(() =>
+      Promise.resolve(
+        new Response(JSON.stringify({ choices: [] }), {
+          status: 400,
+          headers: { "Content-Type": "application/json" },
+        })
+      )
     );
 
     const { getByText } = render(
@@ -121,16 +132,15 @@ describe("ChipDetection", () => {
   });
 
   it("handles valid API response correctly", async () => {
-    ImagePicker.launchImageLibraryAsync.mockResolvedValueOnce({
+    (ImagePicker.launchImageLibraryAsync as jest.Mock).mockResolvedValueOnce({
       canceled: false,
       assets: [{ uri: "test-uri", base64: "test-base64" }],
     });
 
-    global.fetch.mockImplementationOnce(() =>
-      Promise.resolve({
-        ok: true,
-        json: () =>
-          Promise.resolve({
+    jest.spyOn(global, "fetch").mockImplementationOnce(() =>
+      Promise.resolve(
+        new Response(
+          JSON.stringify({
             choices: [
               {
                 message: {
@@ -139,7 +149,9 @@ describe("ChipDetection", () => {
               },
             ],
           }),
-      })
+          { status: 200, headers: { "Content-Type": "application/json" } }
+        )
+      )
     );
 
     const { getByText } = render(