Run api-mock yarn dev in your local (github), It will be started on localhost:3000
Go to www/packages/payment and start dev NODE_CONFIG_ENV=test MOCK_API=true MOCK_API_URL='http://localhost:3000' yarn dev

First, generate encoded tvLifetime that contain the mock states. We can use api-mock bulkchangebehavior endpoint to generate it. We need list of mock states from the file in mock-state folder. This is the Sample CURL
Copy encoded tvLifetime in response data.context and inject it to browser cookies (Find cookie tvl in Developer tools > Application > Cookies, double click column Value and paste the encoded tvLifetime there)
Refresh the test page, it should using the api-mock endpoint - you can check the log in api-mock process.

How to run web with API-Mock

How to Record