Add support to fetch tool versions from packagist

__tests__/packagist.test.ts

@@ -0,0 +1,50 @@
+import * as packagist from '../src/packagist';
+import nock = require('nock');
+
+describe('search function', () => {
+  const mockResponse = {
+    packages: {
+      'test-package': [
+        {
+          require: {
+            php: '8.0.0'
+          },
+          version: '1.0.0'
+        },
+        {
+          version: '2.0.0'
+        }
+      ]
+    }
+  };
+
+  test('should return the version if matching php version is found', async () => {
+    nock('https://repo.packagist.org')
+      .get('/p2/test-package.json')
+      .reply(200, mockResponse);
+    const result = await packagist.search('test-package', '8.0');
+    expect(result).toBe('1.0.0');
+  });
+
+  test('should return null if no matching php version is found', async () => {
+    nock('https://repo.packagist.org')
+      .get('/p2/test-package.json')
+      .reply(200, mockResponse);
+    const result = await packagist.search('test-package', '5.6');
+    expect(result).toBeNull();
+  });
+
+  test('should return null if fetch fails', async () => {
+    nock('https://repo.packagist.org').get('/p2/test-package.json').reply(404);
+    const result = await packagist.search('test-package', '8.0');
+    expect(result).toBeNull();
+  });
+
+  test('should return null if the response is empty', async () => {
+    nock('https://repo.packagist.org')
+      .get('/p2/test-package.json')
+      .reply(200, {error: true, data: '[]'});
+    const result = await packagist.search('test-package', '8.0');
+    expect(result).toBeNull();
+  });
+});