Scrum Breakfast this June will focus on the following guiding concerns: • Understand unit testing fundamentals in Android/iOS development. • Know why we need to write tests, how it helps to control code quality. • Easy to write testable code with MVVM (Model–View–ViewModel) architecture. • CI/CD setup using Jenkins and Gitlab to show unit test coverage.

2. Mobile Apps Unit testing
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3. What is Unit testing
● A unit test is a piece of a code that invokes another piece of code.
● Done during the development (coding phase) of an application by the
developers
● Isolate a section of code and verify its correctness
● A unit may be an individual function, procedure, module, or object
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4. Why writes test?
● Ability to refactor code with confidence
● Proof that your code actually works
● You get a low-level regression-test suite
● It reduces the cost of bugs
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5. Stunt Double
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6. Test Double
“Test double is a generic term for any case where you replace a production
object for testing purposes.”
- Martin Fowler
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7. Why using Test double
● Enable testing
● Ease testing
● Improve testing
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8. Type of Test Double
● Stubs
● Mocks
● Spy/Spies
● Fake
● Dummy
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9. Stubs
● Control indirect inputs to system under test
● Provide “canned responses” to the SUT
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10. Mock
● Used to verify if the SUT call specific
method of collaborator. (Indirect output)
● Behavior verification
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11. Spy
● Like mock, verify interaction
● Keep track of what methods are called, and what
arguments they are called with.
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12. Fake
● Replace a “depended-on component” with a
lighter weight implementation
● Can be used for input or output
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13. Dummy
● Never used
● Satisfy method parameters
● Easy to implement
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14. Why MVVM?
● Models hold application data.
● Views display visual elements and
controls on the screen.
● View models transform model
information into values that can be
displayed on a view.
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15. Android: JUnit Framework
● Antotation
○ @Test, @Before, @After,
@RunWith, @Rule, etc.
● Assertion
○ assertEquals(expected,
actual)
○ assertTrue(condition)
○ assertNotNull(object)
○ ...
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16. Android: Mockito, Mockk
● verify
● mockk
● spyk
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17. iOS Unit test
● Unit tests have their own
target in Xcode and are
written using the XCTest
framework
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18. iOS Unit test
● Setup and Teardown
● Test Assertion
○ Boolean Assertions
○ Nil and Non-nil Assertions
○ Equality and Inequality Assertions
○ Comparable Value Assertions
○ NSException Assertions
○ Failing Unconditionally
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19. iOS Unit test
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20. iOS Unit test
Quick & Nimble

21. iOS Unit test
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22. Code practice
iOS: https://gitlab.com/ducnguyenht/axon-sb-ios-ut/
Android: https://gitlab.com/ducnguyenht/axon-sb-android-ut/
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23. Q&A
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24. Thank you!
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