Fix selectors registration (#105)

* Fix selectors registration

Author: mmarkelov

src/utils.test.ts

@@ -229,7 +229,7 @@ describe('getPlaywrightInstance', () => {
 
     jest.doMock('playwright', () => ({
       firefox: 'firefox',
-      selectors: { register },
+      selectors: { _engines: new Map(), register },
     }))
 
     const selectors = [{ name: 'test', script: 'test' }]

src/utils.ts

@@ -89,9 +89,11 @@ export const getPlaywrightInstance = async (
     const playwright = require('playwright')
     if (selectors) {
       await Promise.all(
-        selectors.map(({ name, script }) =>
-          playwright.selectors.register(name, script),
-        ),
+        selectors.map(({ name, script }) => {
+          if (!playwright.selectors._engines.get(name)) {
+            return playwright.selectors.register(name, script)
+          }
+        }),
       )
     }
     return playwright[browserType]