diff --git a/2a. React/1. Basics/package-lock.json b/2a. React/1. Basics/package-lock.json
index d0f9f75..ed9de59 100644
--- a/2a. React/1. Basics/package-lock.json	
+++ b/2a. React/1. Basics/package-lock.json	
@@ -23,6 +23,9 @@
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+      "resolved": "https://registry.npmjs.org/whatwg-mimetype/-/whatwg-mimetype-4.0.0.tgz",
+      "integrity": "sha512-QaKxh0eNIi2mE9p2vEdzfagOKHCcj1pJ56EEHGQOVxp8r9/iszLUUV7v89x9O1p/T+NlTM5W7jW6+cz4Fq1YVg==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/whatwg-url": {
+      "version": "14.2.0",
+      "resolved": "https://registry.npmjs.org/whatwg-url/-/whatwg-url-14.2.0.tgz",
+      "integrity": "sha512-De72GdQZzNTUBBChsXueQUnPKDkg/5A5zp7pFDuQAj5UFoENpiACU0wlCvzpAGnTkj++ihpKwKyYewn/XNUbKw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "tr46": "^5.1.0",
+        "webidl-conversions": "^7.0.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
@@ -5722,6 +6460,45 @@
         "url": "https://github.com/chalk/ansi-styles?sponsor=1"
       }
     },
+    "node_modules/ws": {
+      "version": "8.18.2",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.18.2.tgz",
+      "integrity": "sha512-DMricUmwGZUVr++AEAe2uiVM7UoO9MAVZMDu05UQOaUII0lp+zOzLLU4Xqh/JvTqklB1T4uELaaPBKyjE1r4fQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/xml-name-validator": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/xml-name-validator/-/xml-name-validator-5.0.0.tgz",
+      "integrity": "sha512-EvGK8EJ3DhaHfbRlETOWAS5pO9MZITeauHKJyb8wyajUfQUenkIg2MvLDTZ4T/TgIcm3HU0TFBgWWboAZ30UHg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/xmlchars": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/xmlchars/-/xmlchars-2.2.0.tgz",
+      "integrity": "sha512-JZnDKK8B0RCDw84FNdDAIpZK+JuJw+s7Lz8nksI7SIuU3UXJJslUthsi+uWBUYOwPFwW7W7PRLRfUKpxjtjFCw==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/yallist": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-3.1.1.tgz",
diff --git a/2a. React/1. Basics/package.json b/2a. React/1. Basics/package.json
index 24c39c4..0c4815e 100644
--- a/2a. React/1. Basics/package.json	
+++ b/2a. React/1. Basics/package.json	
@@ -27,6 +27,9 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.25.0",
+    "@testing-library/jest-dom": "^6.6.3",
+    "@testing-library/react": "^16.3.0",
+    "@testing-library/user-event": "^14.6.1",
     "@types/node": "^22.15.30",
     "@types/react": "^19.1.2",
     "@types/react-dom": "^19.1.2",
@@ -36,6 +39,7 @@
     "eslint-plugin-react-hooks": "^5.2.0",
     "eslint-plugin-react-refresh": "^0.4.19",
     "globals": "^16.0.0",
+    "jsdom": "^26.1.0",
     "tw-animate-css": "^1.3.4",
     "typescript": "~5.8.3",
     "typescript-eslint": "^8.30.1",
diff --git a/2a. React/1. Basics/setup-tests.ts b/2a. React/1. Basics/setup-tests.ts
new file mode 100644
index 0000000..6b2ee98
--- /dev/null
+++ b/2a. React/1. Basics/setup-tests.ts	
@@ -0,0 +1,13 @@
+import "@testing-library/jest-dom/vitest";
+import { vi } from "vitest";
+
+vi.stubGlobal(
+  "ResizeObserver",
+  vi.fn(() => ({
+    observe: vi.fn(),
+    unobserve: vi.fn(),
+    disconnect: vi.fn(),
+  })),
+);
+
+Element.prototype.scrollIntoView = vi.fn();
diff --git a/2a. React/1. Basics/src/components/solvro-projects-combobox.test.tsx b/2a. React/1. Basics/src/components/solvro-projects-combobox.test.tsx
index e69de29..b3522fd 100644
--- a/2a. React/1. Basics/src/components/solvro-projects-combobox.test.tsx	
+++ b/2a. React/1. Basics/src/components/solvro-projects-combobox.test.tsx	
@@ -0,0 +1,62 @@
+import { describe, it, expect } from "vitest";
+import { render, screen } from "@testing-library/react";
+import { SolvroProjectsCombobox } from "./solvro-projects-combobox";
+import "@testing-library/jest-dom/vitest";
+import { userEvent } from "@testing-library/user-event";
+
+const PROJECT_NAMES = [
+  "Eventownik",
+  "ToPWR",
+  "Planer",
+  "PromoCHATor",
+  "Testownik",
+];
+
+async function clickCombobox() {
+  const user = userEvent.setup();
+  render(<SolvroProjectsCombobox />);
+  const combobox = screen.getByRole("combobox");
+  expect(combobox).toBeInTheDocument();
+  await user.click(combobox);
+  return user;
+}
+
+describe("SolvroProjectsCombobox", () => {
+  it("should render a select prompt", () => {
+    render(<SolvroProjectsCombobox />);
+    const combobox = screen.getByRole("combobox");
+    expect(combobox).toBeInTheDocument();
+    expect(combobox).toHaveTextContent(/^wyszukaj projekt/i);
+  });
+
+  it("should show all options when clicked", async () => {
+    await clickCombobox();
+    const list = screen.getByRole("group");
+    expect(list.children).toHaveLength(PROJECT_NAMES.length);
+    list.childNodes.forEach((option, index) => {
+      expect(option).toHaveTextContent(PROJECT_NAMES[index]);
+    });
+  });
+
+  it("should filter options based on input", async () => {
+    const user = await clickCombobox();
+    const input = screen.getByPlaceholderText("Wyszukaj projekt...");
+    expect(input).toBeInTheDocument();
+    await user.type(input, "ne");
+    const list = screen.getByRole("group");
+    expect(list.children).toHaveLength(2);
+    expect(list.firstChild).toHaveTextContent("Planer");
+    expect(list.lastChild).toHaveTextContent("Eventownik");
+  });
+
+  it("should hide the combobox when selecting an option", async () => {
+    const user = await clickCombobox();
+    const input = screen.getByPlaceholderText("Wyszukaj projekt...");
+    expect(input).toBeInTheDocument();
+    const list = screen.getByRole("group");
+    expect(list).toBeInTheDocument();
+    expect(list.children).toHaveLength(PROJECT_NAMES.length);
+    await user.click(list.children[3]);
+    expect(list).not.toBeInTheDocument();
+  });
+});
diff --git a/2a. React/1. Basics/src/components/solvro-projects-combobox.tsx b/2a. React/1. Basics/src/components/solvro-projects-combobox.tsx
index c2fe01c..976c134 100644
--- a/2a. React/1. Basics/src/components/solvro-projects-combobox.tsx	
+++ b/2a. React/1. Basics/src/components/solvro-projects-combobox.tsx	
@@ -79,7 +79,7 @@ export function SolvroProjectsCombobox() {
                   <CheckIcon
                     className={cn(
                       "mr-2 h-4 w-4",
-                      value === framework.value ? "opacity-100" : "opacity-0"
+                      value === framework.value ? "opacity-100" : "opacity-0",
                     )}
                   />
                   {framework.label}
diff --git a/2a. React/1. Basics/vite.config.ts b/2a. React/1. Basics/vite.config.ts
index 8b096a1..8403377 100644
--- a/2a. React/1. Basics/vite.config.ts	
+++ b/2a. React/1. Basics/vite.config.ts	
@@ -10,4 +10,10 @@ export default defineConfig({
       "@": path.resolve(__dirname, "./src"),
     },
   },
+  // @ts-expect-error: test config is recognised by vitest here
+  test: {
+    environment: "jsdom",
+    globals: true,
+    setupFiles: "./setup-tests.ts",
+  },
 });