SpaceX

Tech stack:

• Coroutines
• Flows
• Room
• Paging 3 library

For API I used V4 as V3 is deprecated and doesn't serve any new data after November 2020

Features:

• Paging
• Filtering
• Continuous swipe
• Swipe to refresh

Known bugs and cut corners

• Filtering doesn't work offline (local filtering would require more logic to integrate with paging lib, decided to cut it out for simplicity)
• Funny behaviour of Launches top separator, it's because of paging library, to fix it separator should be moved to top adapter.
• Null links doesn't work (implementation should't show action option if link is null)
• Ongoing mission dates are showing with minus sign (a little bit of logic, the requirement was to show +/- depending on state I've cut it out)
• No empty results pages
• No multi year filtering.

Espresso:

I really just made very basic UI tests. I guess for task like this setting up infrastructure for proper espresso tests would be too much (mock web server, hilt integration, okhttp idling resource etc, possibly Kotlin DSL etc..).

Findings

I found this task as a good opportunity for trying and assessing couple of new things. First of all paging 3 library.

Paging 3

Pros:

• Quite easy integration of paging
• Support of room for offline features

Cons:

• Not unit testable (supposedly there's a plan by Google devs to make it testable)
• Some APIs are very clunky to use
• Poisons every architectural layer with kinda black box closed APIs
• Definitely not ready yet, a lot of experimental APIs

Verdict:

Very nice lib for startups or smaller apps/features, might be risky to use in bigger projects in flagship features even when ready.

Flows

Pros:

• Seamlessly integrates with each layer of coroutine based project
• Powerful and clean APIs
• More readable than RxJava
• Can replace both RxJava and LiveData at once
• Support for android lifecycle in presentation layer

Cons:

• Lot of deprecated APIs
• Difficult to test (probably little bit more compared to RxJava)
• As a replacement for LiveData in viewmodels, steeper learning curve.
• Sometimes not clear online documentation.

Verdict:

Flows as a replacement for RxJava + LiveData worked really good. Adds bit of complexity in viewmodels but having unified API is really worth it.