diff --git a/tests/shared-ignore-functions.test.mjs b/tests/shared-ignore-functions.test.mjs
new file mode 100644
index 0000000..0466f48
--- /dev/null
+++ b/tests/shared-ignore-functions.test.mjs
@@ -0,0 +1,71 @@
+import test from 'node:test';
+import assert from 'node:assert';
+import { mkdtempSync, writeFileSync, mkdirSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import {
+  isNonProductDir,
+  isNonProductPath,
+  walkFiles
+} from '../cli/shared-ignore.mjs';
+
+test('isNonProductDir identifies detection ignore dirs correctly', (t) => {
+  assert.strictEqual(isNonProductDir('tests'), true);
+  assert.strictEqual(isNonProductDir('src'), false);
+  assert.strictEqual(isNonProductDir('examples'), true);
+
+  // Honours config override
+  assert.strictEqual(
+    isNonProductDir('tests', { detection: { includeNonProduct: true } }),
+    false
+  );
+});
+
+test('isNonProductPath handles deep paths correctly', (t) => {
+  assert.strictEqual(isNonProductPath('src/tests/helper.js'), true);
+  assert.strictEqual(isNonProductPath('src/components/button.jsx'), false);
+  assert.strictEqual(isNonProductPath('examples/basic/index.js'), true);
+
+  // Honours config override
+  assert.strictEqual(
+    isNonProductPath('src/tests/helper.js', { detection: { includeNonProduct: true } }),
+    false
+  );
+
+  // Handles undefined/empty
+  assert.strictEqual(isNonProductPath(null), false);
+  assert.strictEqual(isNonProductPath(''), false);
+});
+
+test('walkFiles recursively visits files and respects options', (t) => {
+  const tmpDir = mkdtempSync(join(tmpdir(), 'docguard-test-walkfiles-'));
+
+  mkdirSync(join(tmpDir, 'src'));
+  writeFileSync(join(tmpDir, 'src', 'index.js'), 'console.log("hello");');
+
+  mkdirSync(join(tmpDir, '.hidden'));
+  writeFileSync(join(tmpDir, '.hidden', 'config.json'), '{}');
+
+  mkdirSync(join(tmpDir, 'node_modules'));
+  writeFileSync(join(tmpDir, 'node_modules', 'pkg.js'), '');
+
+  const visited = [];
+  const complete = walkFiles(tmpDir, (file) => visited.push(file));
+
+  assert.strictEqual(complete, true);
+  // Default ignores node_modules but .hidden depends on skipDotEntries
+  assert.strictEqual(visited.length, 1);
+  assert.ok(visited[0].endsWith('index.js'));
+
+  // Test keeping dot entries conditionally
+  const visitedKeepDot = [];
+  walkFiles(tmpDir, (file) => visitedKeepDot.push(file), {
+    keepDot: (entry) => entry === '.hidden' || entry === 'config.json'
+  });
+
+  assert.strictEqual(visitedKeepDot.length, 2);
+  assert.ok(visitedKeepDot.some(f => f.endsWith('index.js')));
+  assert.ok(visitedKeepDot.some(f => f.endsWith('config.json')));
+
+  rmSync(tmpDir, { recursive: true, force: true });
+});