Learning Android Development

Android Reading a Text File during Test

Useful to create mock JSON results etc.

Photo by Josh Applegate on Unsplash

If you search on how can Android read a text file, you can find several solutions on Stackoverflow. However, they all need context to read the file either from res or asset folder.

// file store in /assets
val inputStream = context.assets.open("test.txt")
// or file store in /res/raw
val inputStream = context.resources.openRawResource(R.raw.test)

In unit testing, we will like to avoid using context. With that, how can we read from a file?

E.g. will be useful for doing Mock Web Service test as below

Android Mock Server for UnitTest

Java classLoader came to rescue

Apparently we can read a file using classLoader

val inputStream = javaClass.classLoader?.getResourceAsStream(fileName)

With this, we can read the file from the resources folder, without needing any Context.