chore(refactor): added unit test file for findConfigFile

Author: Chrilleweb

packages/cli/test/unit/core/helpers/findConfigFile.test.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import fs from 'fs';
+import path from 'path';
+import os from 'os';
+import { findConfigFile } from '../../../../src/core/helpers/findConfigFile.js';
+
+describe('findConfigFile', () => {
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'find-config-test-'));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  it('returns the path when the config file exists in the given directory', () => {
+    const file = 'dotenv-diff.config.json';
+    fs.writeFileSync(path.join(tmpDir, file), '{}');
+
+    const result = findConfigFile(tmpDir, file);
+
+    expect(result).toBe(path.resolve(tmpDir, file));
+  });
+
+  it('finds the config file in a parent directory', () => {
+    const file = 'dotenv-diff.config.json';
+    fs.writeFileSync(path.join(tmpDir, file), '{}');
+
+    const child = path.join(tmpDir, 'subdir');
+    fs.mkdirSync(child);
+
+    const result = findConfigFile(child, file);
+
+    expect(result).toBe(path.resolve(tmpDir, file));
+  });
+
+  it('finds the config file multiple levels up', () => {
+    const file = 'dotenv-diff.config.json';
+    fs.writeFileSync(path.join(tmpDir, file), '{}');
+
+    const deep = path.join(tmpDir, 'a', 'b', 'c');
+    fs.mkdirSync(deep, { recursive: true });
+
+    const result = findConfigFile(deep, file);
+
+    expect(result).toBe(path.resolve(tmpDir, file));
+  });
+
+  it('returns null when the config file does not exist anywhere in the tree', () => {
+    const child = path.join(tmpDir, 'subdir');
+    fs.mkdirSync(child);
+
+    const result = findConfigFile(child, 'nonexistent.config.json');
+
+    expect(result).toBeNull();
+  });
+
+  it('prefers the config file in the starting directory over a parent one', () => {
+    const file = 'dotenv-diff.config.json';
+    fs.writeFileSync(path.join(tmpDir, file), '{"root":true}');
+
+    const child = path.join(tmpDir, 'subdir');
+    fs.mkdirSync(child);
+    fs.writeFileSync(path.join(child, file), '{"child":true}');
+
+    const result = findConfigFile(child, file);
+
+    expect(result).toBe(path.resolve(child, file));
+  });
+
+  it('works with different file names', () => {
+    const file = 'dotenv-diff.baseline.json';
+    fs.writeFileSync(path.join(tmpDir, file), '{}');
+
+    const result = findConfigFile(tmpDir, file);
+
+    expect(result).toBe(path.resolve(tmpDir, file));
+  });
+
+  it('returns null when starting from a directory with no ancestors containing the file', () => {
+    // Use a real path that definitely won't have the file
+    const result = findConfigFile(
+      os.tmpdir(),
+      '__nonexistent_config_xyz__.json',
+    );
+    expect(result).toBeNull();
+  });
+});