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TDD - EP 2
codurance.com
Testing anti-patterns - The mockery,
The inspector, The Generous leftovers
and The local hero
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Matheus Marabesi
Hello there, you can call me Marabesi,
But my name is Matheus Marabesi, I work at Codurance as a
Software Craftsperson.
I enjoy talking about anything related to: testing, patterns and
gamification.
You can find me at @MatheusMarabesi or https://marabesi.com
Codurance
Crafting Code
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Giulio Perrone
Hello there!
As you may have guessed, my name is Giulio and I work at
Codurance as a Software Craftsperson!
I enjoy writing katas, discussing algorithms and playing
video-games.
Codurance
Crafting Code
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1. Intro - Recap
2. The mockery - MM
3. The inspector - GP
4. The Generous leftovers - MM
5. The local hero - GP
6. Wrapping up
Crafting code
Agenda
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1. Recap
Episode 1, testing assertions
Getting started
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The Liar
The Giant
The Mockery
The Inspector
Generous Leftovers
The Local Hero
The Nitpicker
The Secret Catcher
The Dodger
The Loudmouth
Anti patterns
The Greedy Catcher
Excessive Setup
The Sequencer
Hidden Dependency
The Enumerator
The Stranger
The Operating System Evangelist
Success Against All Odds
The Free Ride
The One
The Peeping Tom
The Slow Poke
James Carr - TDD Anti-Patterns
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The Liar 4
The Giant 5
The Mockery
The Inspector
Generous Leftovers
The Local Hero
The Nitpicker
The Secret Catcher
The Dodger
The Loudmouth
Anti patterns
The Greedy Catcher
Excessive Setup 3
The Sequencer
Hidden Dependency
The Enumerator
The Stranger
The Operating System Evangelist
Success Against All Odds
The Free Ride
The One
The Peeping Tom
The Slow Poke 6
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Anti patterns - Survey takeaways
1. Survey notes: Javascript, PHP and Java were the most used programming languages
2. Survey notes: Practitioners usually informally learn TDD
3. The anti patterns covered were related to test last
4. Subjects we touched around testability: SOLID, Object calisthenics, Non-determinism and the
test pyramid
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2. Anti-patterns - Episode 2
The mockery, The inspector, Generous
leftovers and The local hero
Getting started
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The Liar
The Giant
The Mockery
The Inspector
Generous Leftovers
The Local Hero
The Nitpicker
The Secret Catcher
The Dodger
The Loudmouth
Anti patterns
The Greedy Catcher
Excessive Setup
The Sequencer
Hidden Dependency
The Enumerator
The Stranger
The Operating System Evangelist
Success Against All Odds
The Free Ride
The One
The Peeping Tom
The Slow Poke
James Carr - TDD Anti-Patterns
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The Liar
The Giant
The Mockery 1
The Inspector 7
Generous Leftovers 5
The Local Hero 7
The Nitpicker
The Secret Catcher
The Dodger
The Loudmouth
Anti patterns
The Greedy Catcher
Excessive Setup
The Sequencer
Hidden Dependency
The Enumerator
The Stranger
The Operating System Evangelist
Success Against All Odds
The Free Ride
The One
The Peeping Tom
The Slow Poke
James Carr - TDD Anti-Patterns
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Survey
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2. The mockery - 🏆1
Sometimes mocking can be good, and handy.
But sometimes developers can lose themselves
and in their effort to mock out what isn’t being
tested. In this case, a unit test contains so many
mocks, stubs, and/or fakes that the system under
test isn’t even being tested at all, instead data
returned from mocks is what is being tested.
Crafting code
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class PaymentService(
private val userRepository: UserRepository,
private val paymentGateway: PaymentGateway
) {
fun process(
user: User,
paymentDetails: PaymentDetails
): Boolean {
if (userRepository.exists(user)) {
return paymentGateway.pay(paymentDetails)
}
return false
}
}
Repository - Kotlin
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class PaymentService(
private val userRepository: UserRepository,
private val paymentGateway: PaymentGateway
) {
fun process(
user: User,
paymentDetails: PaymentDetails
): Boolean {
if (userRepository.exists(user)) {
return paymentGateway.pay(paymentDetails)
}
return false
}
}
Repository - Kotlin
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class PaymentService(
private val userRepository: UserRepository,
private val paymentGateway: PaymentGateway
) {
fun process(
user: User,
paymentDetails: PaymentDetails
): Boolean {
if (userRepository.exists(user)) {
return paymentGateway.pay(paymentDetails)
}
return false
}
}
Repository - Kotlin
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class PaymentService(
private val userRepository: UserRepository,
private val paymentGateway: PaymentGateway
) {
fun process(
user: User,
paymentDetails: PaymentDetails
): Boolean {
if (userRepository.exists(user)) {
return paymentGateway.pay(paymentDetails)
}
return false
}
}
Repository - Kotlin
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class TestPaymentService {
private val userRepository: UserRepository = mockk()
private val paymentGateway: PaymentGateway = mockk()
private val paymentService = PaymentService(
userRepository,
paymentGateway
)
@Test
fun paymentServiceProcessPaymentFor() {
val user: User = User()
every { userRepository.exists(any()) } returns true
every { paymentGateway.pay(any()) } returns true
assertTrue(paymentService.process(user, PaymentDetails()))
}
}
Repository - Kotlin
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class TestPaymentService {
private val userRepository: UserRepository = mockk()
private val paymentGateway: PaymentGateway = mockk()
private val paymentService = PaymentService(
userRepository,
paymentGateway
)
@Test
fun paymentServiceProcessPaymentForUser() {
val user: User = User()
every { userRepository.exists(any()) } returns true
every { paymentGateway.pay(any()) } returns true
assertTrue(paymentService.process(user, PaymentDetails()))
}
}
Repository - Kotlin
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class TestPaymentService {
private val userRepository: UserRepository = mockk()
private val paymentGateway: PaymentGateway = mockk()
private val paymentService = PaymentService(
userRepository,
paymentGateway
)
@Test
fun paymentServiceProcessPaymentForUser() {
val user: User = User()
every { userRepository.exists(any()) } returns true
every { paymentGateway.pay(any()) } returns true
assertTrue(paymentService.process(user, PaymentDetails()))
}
}
Repository - Kotlin
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class TestPaymentService {
private val userRepository: UserRepository = mockk()
private val paymentGateway: PaymentGateway = mockk()
private val paymentService = PaymentService(
userRepository,
paymentGateway
)
@Test
fun paymentServiceProcessPaymentForUser() {
val user: User = User()
every { userRepository.exists(any()) } returns true
every { paymentGateway.pay(any()) } returns true
assertTrue(paymentService.process(user, PaymentDetails()))
}
}
Repository - Kotlin
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Mocks, stubs, fake, spies
https://blog.cleancoder.com/uncle-bob/2014/05/14/TheLittleMocker.html
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user ca/can’t do certain actions
in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user ca/can’t do certain actions
in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user can/can’t do certain
actions in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user ca/can’t do certain actions
in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user ca/can’t do certain actions
in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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DUMMIES
You pass in something, and you don’t care who it is used,
often the object is not used at all.
STUB
Opposed to dummies, stubs are objects created in a way
that you do care how they are used. For example, to tricky
an authorization to test if the user ca/can’t do certain actions
in the system.
SPIES
To assert that a method was called by the system under test,
as the post by [1]: “You can use Spies to see inside the
workings of the algorithms you are testing”.
True mocks, stubs, dummies, spies, fakes
TRUE MOCKS
Is interested in the behavior, instead of return of functions. It
cares about which functions were invoked, with what
arguments and how often.
FAKES
Fakes have business logic, so it can drive the system under
test with different sets of data.
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createDummie(FileRepository::class);
$repository = $this->createDummie(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$assembler->packVersion(new Release());
}
Stub - PHP
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public function test_should_generate_new_version()
{
$file = new File('1', 'myfile.json', 'src/myfile.json', '{}');
$fileRepository = $this->createStub(FileRepository::class);
$fileRepository->method('findFile')
->willReturn(
$file
);
$branch = 'master';
$filesToReleaseRepository =
$this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly($this->findVersion, $fileRepository, $branch,
$filesToReleaseRepository);
$assembler->setFilesToWriteRelease([$file]);
Stub - PHP
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public function test_should_generate_new_version()
{
$file = new File('1', 'myfile.json', 'src/myfile.json', '{}');
$fileRepository = $this->createStub(FileRepository::class);
$fileRepository->method('findFile')
->willReturn(
$file
);
$branch = 'master';
$filesToReleaseRepository =
$this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly($this->findVersion, $fileRepository, $branch,
$filesToReleaseRepository);
$assembler->setFilesToWriteRelease([$file]);
Stub - PHP
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public function test_should_generate_new_version()
{
$file = new File('1', 'myfile.json', 'src/myfile.json', '{}');
$fileRepository = $this->createStub(FileRepository::class);
$fileRepository->method('findFile')
->willReturn(
$file
);
$branch = 'master';
$filesToReleaseRepository =
$this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly($this->findVersion, $fileRepository, $branch,
$filesToReleaseRepository);
$assembler->setFilesToWriteRelease([$file]);
Stub - PHP
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public function test_should_generate_new_version()
{
$file = new File('1', 'myfile.json', 'src/myfile.json', '{}');
$fileRepository = $this->createStub(FileRepository::class);
$fileRepository->method('findFile')
->willReturn(
$file
);
$branch = 'master';
$filesToReleaseRepository =
$this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly($this->findVersion, $fileRepository, $branch,
$filesToReleaseRepository);
$assembler->setFilesToWriteRelease([$file]);
Stub - PHP
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The library and the anti-pattern are different things
Mockery != Mockery
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● Historic reasons / TDD styles?
● As simple as the code is, the easiest is to overuse it
● Also, no experience in TDD
Root cause
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3. The inspector - 🏆9
A unit test that violates encapsulation in an
effort to achieve 100% code coverage, but
knows so much about what is going on in the
object that any attempt to refactor will break
the existing test and require any change to
be reflected in the unit test.
Crafting code
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$release = $assembler->packVersion(new Release());
$this->assertEquals('0.0.12', $release->getVersion());
}
Getters and setters - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$release = $assembler->packVersion(new Release());
$this->assertEquals('0.0.12', $release->getVersion());
}
Getters and setters - PHP
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public function test_should_throw_error_if_no_files_are_found_to_release()
{
$this->expectException(NoFilesToRelease::class);
$fileRepository = $this->createStub(FileRepository::class);
$repository = $this->createStub(FilesToReleaseRepository::class);
$assembler = new Assembly(
$this->findVersion, $fileRepository, 'master', $repository
);
$assembler->setFilesToWriteRelease([]);
$release = $assembler->packVersion(new Release());
$this->assertEquals('0.0.12', $release->getVersion());
}
Getters and setters - PHP
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No content
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package com.mypackage
class EmployeeUnitTest {
private var company: Company = CompanyBuilder.build()
init {
FieldUtils.writeField(company, "id", CompanyId.randomId(), true)
}
}
Reflection- Kotlin
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package com.mypackage
class EmployeeUnitTest {
private var company: Company = CompanyBuilder.build()
init {
FieldUtils.writeField(company, "id", CompanyId.randomId(), true)
}
}
Reflection- Kotlin
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package com.mypackage
class EmployeeUnitTest {
private var company: Company = CompanyBuilder.build()
init {
FieldUtils.writeField(company, "id", CompanyId.randomId(), true)
}
}
Reflection- Kotlin
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public void testSquare()
{
Class classToTest = SomeApplicationClass.class;
Method privateMethod = classToTest.getMethod(
"computeSquare", new Class[]{Integer.class}
);
String result = (String) privateMethod.invoke(
new Integer(3)
);
assertEquals("9", result);
}
Reflection - Java
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public void testSquare()
{
Class classToTest = SomeApplicationClass.class;
Method privateMethod = classToTest.getMethod(
"computeSquare", new Class[]{Integer.class}
);
String result = (String) privateMethod.invoke(
new Integer(3)
);
assertEquals("9", result);
}
Reflection - Java
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public void testSquare()
{
Class classToTest = SomeApplicationClass.class;
Method privateMethod = classToTest.getMethod(
"computeSquare", new Class[]{Integer.class}
);
String result = (String) privateMethod.invoke(
new Integer(3)
);
assertEquals("9", result);
}
Reflection - Java
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public void testSquare()
{
Class classToTest = SomeApplicationClass.class;
Method privateMethod = classToTest.getMethod(
"computeSquare", new Class[]{Integer.class}
);
String result = (String) privateMethod.invoke(
new Integer(3)
);
assertEquals("9", result);
}
Reflection - Java
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public void testSquare()
{
Class classToTest = SomeApplicationClass.class;
Method privateMethod = classToTest.getMethod(
"computeSquare", new Class[]{Integer.class}
);
String result = (String) privateMethod.invoke(
new Integer(3)
);
assertEquals("9", result);
}
Reflection - Java
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● Reflection - Encapsulation
● Did I hear coverage?
Points of attention
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● Lack of practice on TDD
● Oriented to coverage
Root cause
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4. Generous Leftovers - 🏆5
An instance where one unit test creates
data that is persisted somewhere, and
another test reuses the data for its own
devious purposes. If the “generator” is
ran afterward, or not at all, the test using
that data will outright fail.
Crafting code
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No content
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No content
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
✅
❌
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test('Testing twice', () => {
mockFn.mockClear();
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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test('Testing twice', () => {
mockFn.mockClear();
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
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const mockFn = jest.fn();
function fnUnderTest(args1) {
mockFn(args1);
}
test('Testing once', () => {
fnUnderTest('first-call');
expect(mockFn).toHaveBeenCalledWith('first-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
test('Testing twice', () => {
mockFn.mockClear();
fnUnderTest('second-call');
expect(mockFn).toHaveBeenCalledWith('second-call');
expect(mockFn).toHaveBeenCalledTimes(1);
});
Jest - Javascript
✅
✅
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● Persistent fixtures can become a source of errors
● Your tests are coupled on a specific sequence to be executed
● Persistent fixtures can make test slower
Points of attention
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● Lack of practice on TDD
● Mixing different types of tests, integration/unit/end-to-end
Root cause
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5. The local hero - 🏆7
A test case that is dependent on
something specific to the development
environment it was written on in order
to run. The result is the test passes on
development boxes, but fails when
someone attempts to run it elsewhere.
Crafting code
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No content
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import { Component } from 'react';
import Button from '../../buttons/primary/Primary';
import '../../../../scss/shake-horizontal.scss';
import './survey.scss';
const config = {
surveyUrl: process.env.REACT_APP_SURVEY_URL || '',
}
const survey = config.surveyUrl;
const mapStateToProps = state => ({
user: state.userReducer.user,
});
export class Survey extends Component {
Javascript - ReactJs
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import { Component } from 'react';
import Button from '../../buttons/primary/Primary';
import '../../../../scss/shake-horizontal.scss';
import './survey.scss';
const config = {
surveyUrl: process.env.REACT_APP_SURVEY_URL || '',
}
const survey = config.surveyUrl;
const mapStateToProps = state => ({
user: state.userReducer.user,
});
export class Survey extends Component {
Javascript - ReactJs
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import { Component } from 'react';
import Button from '../../buttons/primary/Primary';
import '../../../../scss/shake-horizontal.scss';
import './survey.scss';
const config = {
surveyUrl: process.env.REACT_APP_SURVEY_URL || '',
}
const survey = config.surveyUrl;
const mapStateToProps = state => ({
user: state.userReducer.user,
});
export class Survey extends Component {
Javascript - ReactJs
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import { Component } from 'react';
import Button from '../../buttons/primary/Primary';
import '../../../../scss/shake-horizontal.scss';
import './survey.scss';
const config = {
surveyUrl: process.env.REACT_APP_SURVEY_URL || '',
}
const survey = config.surveyUrl;
const mapStateToProps = state => ({
user: state.userReducer.user,
});
export class Survey extends Component {
Javascript - ReactJs
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import { Component } from 'react';
import Button from '../../buttons/primary/Primary';
import '../../../../scss/shake-horizontal.scss';
import './survey.scss';
const config = {
surveyUrl: process.env.REACT_APP_SURVEY_URL || '',
}
const survey = config.surveyUrl;
const mapStateToProps = state => ({
user: state.userReducer.user,
});
export class Survey extends Component {
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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test('show up button when loading is done and skip prop is true', () => {
const user = { uid: 'uhiuqwqw-k-woqk-wq--qw' };
const wrapper = mount();
wrapper.setState({
loading: false
});
expect(wrapper.find(Button).length).toBe(1);
});
Javascript - ReactJs
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No content
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No content
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No content
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● File system
● Dependencies on the operating system
● External configuration management
Points of attention
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6. Wrapping up
We are almost done!
Crafting code
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● The Mockery
● The inspector
● The generous leftovers
● The local hero
● and many more!
What we covered
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https://www.codurance.com/publications/building-testing-culture
https://www.codurance.com/publications/tdd-anti-patterns-chapter-1
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https://www.codurance.com/publications/building-testing-culture
https://www.codurance.com/publications/building-testing-culture
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Matheus Marabesi
Hello there, you can call me Marabesi,
But my name is Matheus Marabesi, I work at Codurance as a
Software craftsperson.
I enjoy talking about anything related to: testing, patterns and
gamification.
You can find me at @MatheusMarabesi or https://marabesi.com
Codurance
Crafting Code
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Giulio Perrone
Hello there!
As you may have guessed, my name is Giulio and I work at
Codurance as a Software Craftsperson!
I enjoy writing katas, discussing algorithms and playing
video-games.
Codurance
Crafting Code