TDD anti patterns - episode 3 - With Juan Pablo

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TDD - EP 3 codurance.com Testing anti-patterns - The nitpicker,

The secret catcher, The dodger, The Loudmouth

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

1. Intro - Recap 2. The nitpicker 3. The secret

catcher 4. The dodger 5. The Loudmouth 6. Wrapping up Crafting code Agenda

1. Recap Episode 1, Episode 2 Getting started

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

The Liar 4 The Giant 5 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 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

The Liar 4 The Giant 5 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 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

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. Survey notes: Companies argue that TDD requires more time to complete a task and the team don't have time for it

2. Anti-patterns - Episode 3 The nitpicker, The secret catcher,

The dodger and The Loudmounth Getting started

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

The Liar The Giant The Mockery The Inspector Generous Leftovers

The Local Hero The Nitpicker8 The Secret Catcher7 The Dodger8 The Loudmouth8 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

Survey

Survey 54.6% Agree

Survey 45.4% Neutral + disagree

2. The nitpicker - 🏆8 A unit test which compares

a complete output when it’s really only interested in small parts of it, so the test has to continually be kept in line with otherwise unimportant details. Endemic in web application testing. Crafting code

public function testDeleteApplication() { $response = $this->postApplication(); $this->assertFalse($response->error); $this->delete('api/application/' .

$response->data) ->assertExactJson([ 'data' => (string) $response->data, 'error' => false ]); } PHP - Laravel

public function testDeleteApplication() { $response = $this->postApplication(); $this->assertFalse($response->error); $this->delete('api/application/' .

$response->data) ->assertJson([ 'data' => (string) $response->data, 'error' => false ]); } PHP - Laravel

public function testDeleteApplication() { $response = $this->postApplication(); $this->assertFalse($response->error); $this->delete('api/application/' .

$response->data) ->assertJson([ 'data' => (string) $response->data, 'error' => false ]); } PHP - Laravel

describe('#getSignedCookies()', function() { it('should create cookies object', function(done) { var

result = CloudfrontUtil.getSignedCookies( 'http://foo.com', defaultParams); expect(result).to.have.property('CloudFront-Policy'); expect(result).to.have.property('CloudFront-Signature'); expect(result).to.have.property('CloudFront-Key-Pair-Id'); done(); }); }); Javascript - chai

describe('#getSignedCookies()', function() { it('should create cookies object', function(done) { var

@Test fun `should calculate CFR correctly by monthly and the

time split works well ( cross a calendar month)`() { val requestBody = """ { skipped code } """.trimIndent() RestAssured .given() .contentType(ContentType.JSON) .body(requestBody) .post("/api/pipeline/metrics") .then() .statusCode(200) .body("changeFailureRate.summary.value", equalTo(30.0F)) .body("changeFailureRate.summary.level", equalTo("MEDIUM")) .body("changeFailureRate.details[0].value", equalTo("NaN")) .body("changeFailureRate.details[1].value", equalTo("NaN")) .body("changeFailureRate.details[2].value", equalTo(30.0F)) } Kotlin - RestAssured

@Test fun `should calculate CFR correctly by monthly and the

• Use what you need • It can be generalized

to other applications (CLI for example) Points of attention

3. The Secret Catcher - 🏆7 A test that at

ﬁrst glance appears to be doing no testing due to the absence of assertions, but as they say, “the devil’s in the details.” The test is really relying on an exception to be thrown when a mishap occurs, and is expecting the testing framework to capture the exception and report it to the user as a failure. Crafting code

Reﬂection - Java

test('it handles error when removing credit card ', async ()

=> { const data = await Payment.asyncData(asyncDataContext); data.paymentMethod = PaymentMethod.CREDIT_CARD; const { getAllByText } = render(Payment, { mocks, data() { return { ...data }; }, }); const [removeButton] = getAllByText(Remove'); await fireEvent.click(removeButton); }); Jest - Javascript

test('it handles error when removing credit card ', async ()

=> { const data = await Payment.asyncData(asyncDataContext); data.paymentMethod = PaymentMethod.CREDIT_CARD; const { getAllByText } = render(Payment, { mocks, data() { return { ...data }; }, }); const [removeButton] = getAllByText('Remove'); await fireEvent.click(removeButton); }); Jest - Javascript

test('it handles error when removing credit card ', async ()

=> { const data = await Payment.asyncData(asyncDataContext); data.paymentMethod = PaymentMethod.CREDIT_CARD; const { getAllByText } = render(Payment, { mocks, data() { return { ...data }; }, }); const [removeButton] = getAllByText('Remove'); await fireEvent.click(removeButton); }); Jest - Javascript 👀

test('it handles error when removing credit card ', async ()

=> { const data = await Payment.asyncData(asyncDataContext); data.paymentMethod = PaymentMethod.CREDIT_CARD; const { getAllByText } = render(Payment, { mocks, data() { return { ...data }; }, }); const [removeButton] = getAllByText('Remove'); await fireEvent.click(removeButton); expect(getByText('Some error')).toBeInTheDocument(); }); Jest - Javascript

Reﬂection - Java

Software engineering unlocked, Dr. McKayla Because well, if, if you

know, a smoke test could also execute a lot of the code base. Actually just, you know, make sure that the code run somehow without verifying that, you know, the inputs and outputs are matching and so on. Dr. Mauricio’s Aniche

• Context matters Points of attention

• Lack of practice on TDD • Oriented to coverage

Root cause

4. The Dodger - 🏆8 A unit test which has

lots of tests for minor (and presumably easy to test) side eﬀects, but never tests the core desired behavior. Sometimes you may ﬁnd this in database access related tests, where a method is called, then the test selects from the database and runs assertions against the result. Crafting code

http://blog.cleancoder.com/uncle-bob/2017/10/03/TestContravariance.html

/** * Tests that objects works as expected. */ public

function testObject(): void { $author = Author::createFromArray($this->getSampleId(), $this->getSampleValues()); $this->assertEquals($this->getSampleId(), $author->getId()); $this->assertEquals($this->getSampleValues()['name']['given'], $author->getNameGiven()); $this->assertEquals($this->getSampleValues()['name']['family'], $author->getNameFamily()); $this->assertEquals($this->getSampleValues()['country'], $author->getCountry()); $this->assertEquals($this->getSampleValues()['org']['name'], $author->getOrgName()); $this->assertEquals($this->getSampleValues()['org']['unit'], $author->getOrgUnit()); $this->assertEquals($this->getSampleValues()['homepage'], $author->getHomepage()); $this->assertEquals($this->getSampleValues()['description'], $author->getDescription()); $this->assertEquals($this->getSampleValues()['image'], $author->getImage()); $this->assertEquals($this->getSampleValues()['identification'], $author->getIdentification()); $this->assertEquals($this->getSampleValues()['identification']['email'], $author->getIdentification('email')); $this->assertEquals([], $author->getIdentification('not exist')); $this->assertEquals($author->checksum(), $author->checksum()); } Drupal - PHP

/** * Tests that objects works as expected. */ public

• 1-1 one test class to one production class •

Focus on implementation details rather than behavior Points of attention

5. The Loudmouth - 🏆8 A unit test (or test

suite) that clutters up the console with diagnostic messages, logging messages, and other miscellaneous chatter, even when tests are passing. Crafting code

None

test.each([['function']])( 'should not bubble up the error when a invalid

source code is provided', (code) => { const strategy = jest.fn(); const result = Reason(code, strategy); expect(strategy).toHaveBeenCalledTimes(0); expect(result).toBeFalsy(); } ); Console log - Javascript

test.each([['function']])( 'should not bubble up the error when a invalid

const reason = function(code, strategy) { try { const ast

= esprima.parseScript(code); if (ast.body.length > 0) { return strategy(ast); } } catch (error) { /* eslint-disable-next-line */ console.warn(error); return false; } }; Console log - Javascript

const reason = function(code, strategy) { try { const ast

const originalConsole = globalThis.console; beforeEach(() => { globalThis.console = {

warn: jest.fn(), error: jest.fn(), log: jest.fn() }; }); afterEach(() => { globalThis.console = originalConsole; }); Console log - Javascript

const originalConsole = globalThis.console; beforeEach(() => { globalThis.console = {

• Clean up if not needed • Threat the logs

as a feature, test drive them Points of attention

6. Wrapping up We are almost done! Crafting code

• The nitpicker • The secret catcher • The dodger

• The Loudmounth • and many more! What we covered

https://www.codurance.com/publications/tdd-anti-patterns-chapter-1 https://www.codurance.com/publications/tdd-anti-patterns-chapter-2

https://www.codurance.com/publications/building-testing-culture https://www.codurance.com/publications/building-testing-culture

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

TDD anti patterns - episode 3 - With Juan Pablo

TDD anti patterns - episode 3 - With Juan Pablo

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