diff --git a/e2e/cli-e2e/tests/collect.e2e.test.ts b/e2e/cli-e2e/tests/collect.e2e.test.ts
index 4a0f9d9fb..efa768b3d 100644
--- a/e2e/cli-e2e/tests/collect.e2e.test.ts
+++ b/e2e/cli-e2e/tests/collect.e2e.test.ts
@@ -38,7 +38,7 @@ describe('CLI collect', () => {
   });
 
   it('should create report.md', async () => {
-    const { code, stderr } = await executeProcess({
+    const { code } = await executeProcess({
       command: 'npx',
       args: [
         '@code-pushup/cli',
@@ -50,7 +50,6 @@ describe('CLI collect', () => {
     });
 
     expect(code).toBe(0);
-    expect(stderr).toBe('');
 
     const md = await readTextFile(path.join(dummyOutputDir, 'report.md'));
 
@@ -60,14 +59,13 @@ describe('CLI collect', () => {
   });
 
   it('should print report summary to stdout', async () => {
-    const { code, stdout, stderr } = await executeProcess({
+    const { code, stdout } = await executeProcess({
       command: 'npx',
       args: ['@code-pushup/cli', '--no-progress', 'collect'],
       cwd: dummyDir,
     });
 
     expect(code).toBe(0);
-    expect(stderr).toBe('');
 
     expect(stdout).toContain('Code PushUp Report');
     expect(stdout).not.toContain('Generated reports');
diff --git a/e2e/cli-e2e/tests/help.e2e.test.ts b/e2e/cli-e2e/tests/help.e2e.test.ts
index 63533b51c..6382952be 100644
--- a/e2e/cli-e2e/tests/help.e2e.test.ts
+++ b/e2e/cli-e2e/tests/help.e2e.test.ts
@@ -10,13 +10,12 @@ describe('CLI help', () => {
   const envRoot = path.join(E2E_ENVIRONMENTS_DIR, nxTargetProject());
 
   it('should print help with help command', async () => {
-    const { code, stdout, stderr } = await executeProcess({
+    const { code, stdout } = await executeProcess({
       command: 'npx',
       args: ['@code-pushup/cli', 'help'],
       cwd: envRoot,
     });
     expect(code).toBe(0);
-    expect(stderr).toBe('');
     expect(removeColorCodes(stdout)).toMatchSnapshot();
   });
 
diff --git a/e2e/create-cli-e2e/tests/init.e2e.test.ts b/e2e/create-cli-e2e/tests/init.e2e.test.ts
index c926e0c7b..d4b7742ac 100644
--- a/e2e/create-cli-e2e/tests/init.e2e.test.ts
+++ b/e2e/create-cli-e2e/tests/init.e2e.test.ts
@@ -13,7 +13,8 @@ import { executeProcess, readJsonFile, readTextFile } from '@code-pushup/utils';
 const fakeCacheFolderName = () =>
   `fake-cache-${new Date().toISOString().replace(/[:.]/g, '-')}`;
 
-describe('create-cli-init', () => {
+/* after a new release of the nx-verdaccio plugin we can enable the test again. For now, it is too flaky to be productive. (5.jan.2025) */
+describe.todo('create-cli-init', () => {
   const workspaceRoot = path.join(E2E_ENVIRONMENTS_DIR, nxTargetProject());
   const testFileDir = path.join(workspaceRoot, TEST_OUTPUT_DIR, 'init');
 
diff --git a/e2e/plugin-eslint-e2e/tests/collect.e2e.test.ts b/e2e/plugin-eslint-e2e/tests/collect.e2e.test.ts
index 7df4feb45..36e6dcd5e 100644
--- a/e2e/plugin-eslint-e2e/tests/collect.e2e.test.ts
+++ b/e2e/plugin-eslint-e2e/tests/collect.e2e.test.ts
@@ -47,14 +47,13 @@ describe('PLUGIN collect report with eslint-plugin NPM package', () => {
   });
 
   it('should run ESLint plugin for flat config and create report.json', async () => {
-    const { code, stderr } = await executeProcess({
+    const { code } = await executeProcess({
       command: 'npx',
       args: ['@code-pushup/cli', 'collect', '--no-progress'],
       cwd: flatConfigDir,
     });
 
     expect(code).toBe(0);
-    expect(stderr).toBe('');
 
     const report = await readJsonFile(
       path.join(flatConfigOutputDir, 'report.json'),
@@ -65,7 +64,7 @@ describe('PLUGIN collect report with eslint-plugin NPM package', () => {
   });
 
   it('should run ESLint plugin for legacy config and create report.json', async () => {
-    const { code, stderr } = await executeProcess({
+    const { code } = await executeProcess({
       command: 'npx',
       args: ['@code-pushup/cli', 'collect', '--no-progress'],
       cwd: legacyConfigDir,
@@ -73,7 +72,6 @@ describe('PLUGIN collect report with eslint-plugin NPM package', () => {
     });
 
     expect(code).toBe(0);
-    expect(stderr).toBe('');
 
     const report = await readJsonFile(
       path.join(legacyConfigOutputDir, 'report.json'),
diff --git a/testing/test-setup/project.json b/testing/test-setup/project.json
index 3db218fb8..320a534e5 100644
--- a/testing/test-setup/project.json
+++ b/testing/test-setup/project.json
@@ -14,6 +14,12 @@
         "assets": ["testing/test-setup/*.md"]
       }
     },
+    "unit-test": {
+      "executor": "@nx/vite:test",
+      "options": {
+        "configFile": "testing/test-setup/vite.config.unit.ts"
+      }
+    },
     "lint": {
       "executor": "@nx/linter:eslint",
       "outputs": ["{options.outputFile}"],
diff --git a/testing/test-setup/src/lib/extend/path.matcher.ts b/testing/test-setup/src/lib/extend/path.matcher.ts
new file mode 100644
index 000000000..39b222412
--- /dev/null
+++ b/testing/test-setup/src/lib/extend/path.matcher.ts
@@ -0,0 +1,122 @@
+import type { SyncExpectationResult } from '@vitest/expect';
+import { expect } from 'vitest';
+import { osAgnosticPath } from '@code-pushup/test-utils';
+
+export type CustomPathMatchers = {
+  toMatchPath: (path: string) => void;
+  toStartWithPath: (path: string) => void;
+  toContainPath: (path: string) => void;
+  toEndWithPath: (path: string) => void;
+};
+
+export type CustomAsymmetricPathMatchers = {
+  /* eslint-disable @typescript-eslint/no-explicit-any */
+  pathToMatch: (path: string) => any;
+  pathToStartWith: (path: string) => any;
+  pathToContain: (path: string) => any;
+  pathToEndWith: (path: string) => any;
+  /* eslint-enable @typescript-eslint/no-explicit-any */
+};
+
+expect.extend({
+  toMatchPath: assertPathMatch,
+  pathToMatch: assertPathMatch,
+  toStartWithPath: assertPathStartWith,
+  pathToStartWith: assertPathStartWith,
+  toContainPath: assertPathContain,
+  pathToContain: assertPathContain,
+  toEndWithPath: assertPathEndWith,
+  pathToEndWith: assertPathEndWith,
+});
+
+function assertPathMatch(
+  actual: string,
+  expected: string,
+): SyncExpectationResult {
+  const normalizedReceived = osAgnosticPath(actual);
+  const normalizedExpected = osAgnosticPath(expected);
+
+  const pass = normalizedReceived === normalizedExpected;
+  return pass
+    ? {
+        message: () => `expected ${actual} not to match path ${expected}`,
+        pass: true,
+        actual,
+        expected,
+      }
+    : {
+        message: () => `expected ${actual} to match path ${expected}`,
+        pass: false,
+        actual,
+        expected,
+      };
+}
+
+function assertPathStartWith(
+  actual: string,
+  expected: string,
+): SyncExpectationResult {
+  const normalizedReceived = osAgnosticPath(actual);
+  const normalizedExpected = osAgnosticPath(expected);
+
+  const pass = normalizedReceived.startsWith(normalizedExpected);
+  return pass
+    ? {
+        message: () => `expected ${actual} not to start with path ${expected}`,
+        pass: true,
+        actual,
+        expected,
+      }
+    : {
+        message: () => `expected ${actual} to start with path ${expected}`,
+        pass: false,
+        actual,
+        expected,
+      };
+}
+
+function assertPathContain(
+  actual: string,
+  expected: string,
+): SyncExpectationResult {
+  const normalizedReceived = osAgnosticPath(actual);
+  const normalizedExpected = osAgnosticPath(expected);
+
+  const pass = normalizedReceived.includes(normalizedExpected);
+  return pass
+    ? {
+        message: () => `expected ${actual} not to contain path ${expected}`,
+        pass: true,
+        actual,
+        expected,
+      }
+    : {
+        message: () => `expected ${actual} to contain path ${expected}`,
+        pass: false,
+        actual,
+        expected,
+      };
+}
+
+function assertPathEndWith(
+  actual: string,
+  expected: string,
+): SyncExpectationResult {
+  const normalizedReceived = osAgnosticPath(actual);
+  const normalizedExpected = osAgnosticPath(expected);
+
+  const pass = normalizedReceived.endsWith(normalizedExpected);
+  return pass
+    ? {
+        message: () => `expected ${actual} not to end with path ${expected}`,
+        pass: true,
+        actual,
+        expected,
+      }
+    : {
+        message: () => `expected ${actual} to end with path ${expected}`,
+        pass: false,
+        actual,
+        expected,
+      };
+}
diff --git a/testing/test-setup/src/lib/extend/path.matcher.unit.test.ts b/testing/test-setup/src/lib/extend/path.matcher.unit.test.ts
new file mode 100644
index 000000000..676b0065c
--- /dev/null
+++ b/testing/test-setup/src/lib/extend/path.matcher.unit.test.ts
@@ -0,0 +1,102 @@
+import { describe, expect, it, vi } from 'vitest';
+import * as testUtils from '@code-pushup/test-utils';
+
+describe('path-matcher', () => {
+  const osAgnosticPathSpy = vi.spyOn(testUtils, 'osAgnosticPath');
+
+  it('should provide "toMatchPath" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'tmp/path/to/file.txt';
+
+    expect(actual).toMatchPath(expected);
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "pathToMatch" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'tmp/path/to/file.txt';
+
+    expect({ path: actual }).toStrictEqual({
+      path: expect.pathToMatch(expected),
+    });
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "toStartWithPath" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'tmp/path/to';
+
+    expect(actual).toStartWithPath(expected);
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "pathToStartWith" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'tmp/path/to';
+
+    expect({ path: actual }).toStrictEqual({
+      path: expect.pathToStartWith(expected),
+    });
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "toContainPath" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'path/to';
+
+    expect(actual).toContainPath(expected);
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "pathToContain" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'path/to';
+
+    expect({ path: actual }).toStrictEqual({
+      path: expect.pathToContain(expected),
+    });
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "toEndWithPath" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'path/to/file.txt';
+
+    expect(actual).toEndWithPath(expected);
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+
+  it('should provide "pathToEndWith" as expect matcher', () => {
+    const actual = String.raw`tmp\path\to\file.txt`;
+    const expected = 'path/to/file.txt';
+
+    expect({ path: actual }).toStrictEqual({
+      path: expect.pathToEndWith(expected),
+    });
+
+    expect(osAgnosticPathSpy).toHaveBeenCalledTimes(2);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(actual);
+    expect(osAgnosticPathSpy).toHaveBeenCalledWith(expected);
+  });
+});
diff --git a/testing/test-setup/src/vitest.d.ts b/testing/test-setup/src/vitest.d.ts
new file mode 100644
index 000000000..801a7667b
--- /dev/null
+++ b/testing/test-setup/src/vitest.d.ts
@@ -0,0 +1,13 @@
+/* eslint-disable @typescript-eslint/consistent-type-definitions */
+import type {
+  CustomAsymmetricPathMatchers,
+  CustomPathMatchers,
+} from './lib/extend/path.matcher.js';
+
+declare module 'vitest' {
+  // eslint-disable-next-line @typescript-eslint/no-empty-object-type
+  interface Assertion extends CustomPathMatchers {}
+  // eslint-disable-next-line @typescript-eslint/no-empty-object-type
+  interface AsymmetricMatchersContaining extends CustomAsymmetricPathMatchers {}
+}
+/* eslint-enable @typescript-eslint/consistent-type-definitions */
diff --git a/testing/test-setup/tsconfig.json b/testing/test-setup/tsconfig.json
index fda68ff3c..465306e46 100644
--- a/testing/test-setup/tsconfig.json
+++ b/testing/test-setup/tsconfig.json
@@ -14,6 +14,9 @@
   "references": [
     {
       "path": "./tsconfig.lib.json"
+    },
+    {
+      "path": "./tsconfig.test.json"
     }
   ]
 }
diff --git a/testing/test-setup/tsconfig.lib.json b/testing/test-setup/tsconfig.lib.json
index 65e232ad4..51167c9db 100644
--- a/testing/test-setup/tsconfig.lib.json
+++ b/testing/test-setup/tsconfig.lib.json
@@ -6,5 +6,10 @@
     "types": ["node"]
   },
   "include": ["src/**/*.ts"],
-  "exclude": []
+  "exclude": [
+    "vite.config.unit.ts",
+    "src/vitest.d.ts",
+    "src/**/*.unit.test.ts",
+    "src/**/*.integration.test.ts"
+  ]
 }
diff --git a/testing/test-setup/tsconfig.test.json b/testing/test-setup/tsconfig.test.json
new file mode 100644
index 000000000..71916ea12
--- /dev/null
+++ b/testing/test-setup/tsconfig.test.json
@@ -0,0 +1,14 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": ["vitest/globals", "vitest/importMeta", "vite/client", "node"]
+  },
+  "include": [
+    "vite.config.unit.ts",
+    "src/vitest.d.ts",
+    "src/**/*.unit.test.ts",
+    "src/**/*.d.ts",
+    "src/**/*.integration.test.ts"
+  ]
+}
diff --git a/testing/test-setup/vite.config.unit.ts b/testing/test-setup/vite.config.unit.ts
new file mode 100644
index 000000000..45688aac5
--- /dev/null
+++ b/testing/test-setup/vite.config.unit.ts
@@ -0,0 +1,28 @@
+/// <reference types="vitest" />
+import { defineConfig } from 'vite';
+import { tsconfigPathAliases } from '../../tools/vitest-tsconfig-path-aliases.js';
+
+export default defineConfig({
+  cacheDir: '../node_modules/.vite/test-setup',
+  test: {
+    reporters: ['basic'],
+    globals: true,
+    cache: {
+      dir: '../node_modules/.vitest',
+    },
+    alias: tsconfigPathAliases(),
+    pool: 'threads',
+    poolOptions: { threads: { singleThread: true } },
+    coverage: {
+      reporter: ['text', 'lcov'],
+      reportsDirectory: '../../coverage/test-setup/unit-tests',
+      exclude: ['**/*.mock.{mjs,ts}', '**/*.config.{js,mjs,ts}'],
+    },
+    environment: 'node',
+    include: ['src/**/*.unit.test.ts'],
+    setupFiles: [
+      '../test-setup/src/lib/reset.mocks.ts',
+      '../test-setup/src/lib/extend/path.matcher.ts',
+    ],
+  },
+});