Are there any patterns / recommended practices for unit testing Typescript. I recently joined a project which uses Angular1 + Typescript and had to introduce unit testing to the code base and it has been painful. A lot of backend API calls (wrapped in services) are being (chained and) invoked in the constructor. Any initialization is being squashed into the constructor. This makes setup of karma tests extremely painful/brittle without a complete refactor for each component. However wrapping initialization code in public methods feel strange to me. Any suggestions?