How to mock local variables using MockK-CodePudding

I have the following simplified code

class Foo() {
    suspend fun bar() {
        val headers = AtomicReference(Metadata())
        val metadata = headers.get()
        if (metadata.keys().size > 0) { // I want it to return a value specified in the test file
            // ...
    }
}

How can I mock AtomicReference or Metadata so that for example headers.get().keys().size returns a specified value and not the real one?

CodePudding user response：

You can mock the constructor of Metadata using Constructor Mocks:

mockkConstructor(Metadata::class)

every { anyConstructed<Metadata>().keys() } returns mockedKeys

Note that mockedKeys of keys is your test data.

See https://mockk.io/#constructor-mocks

Additionally, try to architect your code in a fashion that you don't need to mock any constructor (like for example using inversion of control), you will see that it pays dividends when testing.