The blog post by Gleb Bahmutov discusses strategies to minimize untestable code within web applications by pushing such code to the edges of applications using App Actions and Effects. The article highlights the limitations of the Cypress.io test runner, particularly its inability to spy on or stub fetch requests, suggesting instead that applications should structure themselves to place fetch calls at the boundary with minimal logic. The post introduces Overmind.js, a state management library that clearly separates state manipulation from external effects, allowing for more effective testing by stubbing or spying on thin wrapper methods that handle external interactions. By setting up tests to directly interact with the application's inner code, rather than solely through the DOM, developers can achieve more robust testing scenarios. The blog provides examples of how to utilize these techniques to effectively test applications by synchronously injecting spies and stubs, ensuring that untestable code is minimized.