Mockk - Saeed Masoumi

Transcript

1. Mocking with Mockk Photo by JOSHUA COLEMAN on Unsplash Saeed Masoumi
2. Mocks Aren't Stubs • Mock • initialize -> set expectations -> exercise -> verify • Stub • initialize -> exercise -> verify • Class that implements the interface/class you are faking for testing purposes • But, There is no such difference, call whatever you want (KISS)
3. SUT and DOCs • The System Under Test (SUT) refers to a system that is being tested for correct operation. • Depended On Component (DOC), is a collaborator, component that is required by SUT to fulfill its duties
4. Why Mockk? • Mockito + extra Kotlin-based features • Looks and Feels like Kotlin code
5. How it works • mockk your objects • For every object, set its behavior • verify them
6. How it works val torch = mockk<Torch>() every { torch.turnOn() } returns OFF val status = torch.turnOn() assertEquals(OFF, status) verify { torch.turnOn() }
7. Object Mocking mockkObject(Math) assertEquals(3, Math.sum(1, 2)) every { Math.sum(any(), 2) } returns 22 assertEquals(22, Math.sum(1, 2)) Also can be used for Enum mocking
8. Constructor Mocking mockkConstructor(Torch::class) every { anyConstructed<Torch>().turnOn() } returns OFF assertEquals(OFF, Torch().turnOn()) verify { anyConstructed<Torch>().turnOn() }
9. Constructor Mocking • Call init block • Because sometimes a testing method will return a new instance of an object
10. Extension Function Mocking data class Obj(val value: Int) class Ext { fun Obj.extensionFunc() = value + 5 } with(mockk<Ext>()) { every { Obj(5).extensionFunc() } returns 11 assertEquals(11, Obj(5).extensionFunc()) verify { Obj(5).extensionFunc() } } Object/Class Wide
11. Extension Function Mocking data class Obj(val value: Int) fun Obj.extensionFunc() = value + 5 mockkStatic("com.yourcompany.FileKt") every { Obj(5).extensionFunc() } returns 11 assertEquals(11, Obj(5).extensionFunc()) verify { Obj(5).extensionFunc() } Module Wide
12. Spying • spyk() means a copy of given object which allows to mix mocks and real methods/field • mockk(relaxed = true) (relaxed mock) is a mock with no restriction to set behavior, So it uses simple value like 0 or null for mocked objects
13. Private Mocking class Profile { fun info() = "name: ${name()}, cardNumber ${cardNumber()}" fun name() = "Saeed" private fun cardNumber() = "****" } val mock = spyk<Profile>() every { mock["cardNumber"]() } returns "1234" assertEquals("name: Saeed, cardNumber 1234", mock.info())
14. Private Mocking • recordPrivateCalls in Spyk • Verbose syntax for dynamic calls and property backing fields
 every { mock getProperty "abc" } every { mock setProperty "xyz" value less(5) } every { mock invoke "foo" withArguments listOf("a", "b") } every { mock.property = any() } propertyType Int::class answers { fieldValue += value } •
15. Implement Interface class Profile { fun info() = "name: ${name()}, cardNumber ${cardNumber()}" fun name() = "Saeed" private fun cardNumber() = "****" }
16. Implement Interface open class Profile { fun info() = "name: ${name()}, cardNumber ${cardNumber()}" fun name() = "Saeed" private fun cardNumber() = "****" }
17. Implement Interface open class Profile { fun info() = "name: ${name()}, cardNumber ${cardNumber()}" fun name() = "Saeed" private fun cardNumber() = "****" } interface Disposable { fun dispose() }
18. Implement Interface val mock = spyk<Profile>(moreInterfaces = *arrayOf(Disposable::class)) every { (mock as Disposable).dispose() } answers { println(“disposing") } (mock as Disposable).dispose() // prints disposing
19. Argument Matching // If you leave matcher, a fixed value automatically wrapped in eq matcher every { Math.sum(eq(5), 5) } returns 5 every { Math.sum(less(5), more(5)) } returns 0 every { Math.sum(any(), or(less(2), eq(2))) } returns 1 more, less, eq, or, any
20. Capturing Arguments val slot = slot<Int>() mockkObject(Math) every { Math.sum(a = capture(slot), b = 2) } answers { println(slot.captured) 4 } Math.sum(1, 2) //prints 1 Math.sum(2,3) // prints nothing
21. Capturing Arguments val list = mutableListOf<Int>() mockkObject(Math) every { Math.sum(a = capture(list), b = 2) } returns 4 every { Math.sum(a = capture(list), b = 3) } returns 4 Math.sum(1, 2) Math.sum(2,3) println(list) // prints [1, 2]
22. Excepted Answer every { Math.sum(1, 2) } returns 5 returns: specify that matched call returns one specified value returnsMany: specify that matched call returns value from the list, returning each time next element every { Math.sum(1, 2) } returnsMany listOf(1, 2, 3)
23. Excepted Answer answers { code }: specify that matched call answers with code block scoped with answer scope coAnswers { code }: specify that matched call answers with coroutine code block with answer scope
24. Excepted Answer every { Math.sum(1, 2) } throws Exception("error") throws: specify that matched call throws an exception just Runs: specify that matched call is returning Unit (returns null) every { Math.printSum(1, 2) } just Runs
25. Excepted Answer Also you can pass Answer object to get access to some Call information
26. Additional Answer (returnsMany) every { Math.sum(1, 2) } returns 3 andThen 4 assertEquals(3, Math.sum(1, 2)) assertEquals(4, Math.sum(1, 2))
27. Additional Answer (returnsMany) every { Math.sum(1, 2) } returns 3 andThen 4 andThenThrows assertEquals(3, Math.sum(1, 2)) assertEquals(4, Math.sum(1, 2))
28. Additional Answer (returnsMany) every { Math.sum(1, 2) } returns 3 andThen 4 andThenThrows andThenThen { } assertEquals(3, Math.sum(1, 2)) assertEquals(4, Math.sum(1, 2))
29. Additional Answer (returnsMany) every { Math.sum(1, 2) } returns 3 andThen 4 andThenThrows andThenThen { } coAndThen { } assertEquals(3, Math.sum(1, 2)) assertEquals(4, Math.sum(1, 2))
30. Additional Answer (returnsMany) every { Math.sum(1, 2) } returns 3 andThen 4 andThenThrows andThenThen { } coAndThen { } answer { arg(1) + 4 } assertEquals(3, Math.sum(1, 2)) assertEquals(4, Math.sum(1, 2))
31. Behavior Verification You can add different behaviors to verify DSL. Here are all possible DSLs for verification verify { } verifyAll { } verifySequence { } verifyOrder { }
32. Behavior Verification Orders: verify(ordering = Ordering.ALL) { } • Unordered • Ordered • Sequence -> exact sequence happed • All -> without any interactions •
33. Behavior Verification Check call count with atLeast, atMost or exactly or wasNot Called: verify(atLeast = 3) { } verify(atMost = 2) { } verify(exactly = 1) { } verify(atLeast = 3,atMost = 5) { } verify { torch.turnOn() wasNot Called }
34. Behavior Verification To verify concurrent operations you can use: verify(timeout = 2000){ } To negate the conditions just enable inverse mode verify(inverse = true){ }
35. Coroutines Support Just add co as a prefix coEvery coVerify coMatch coAssert coRun coAnswers coInvoke