3 Design Patterns and Architecture Decisions you must use in your project Elias Nogueira

Elias Nogueira I help professional software engineers (backend, frontend, qa) to develop their quality mindset and deliver bug-free software so they become top-level engineers and get hired for the best positions in the market. 🏢 Backbase 👨💻‍‍ Principal Software Engineer 📍 Utrecht, the Netherlands 🌐 eliasnogueira.com 🐦 @eliasnogueira bit.ly/eliasnogueira

Base Test Class

Base Test Class It is a simple approach to set up a shared initialization and cleanup in your tests. We commonly categorize it as a Testing pattern. The problem we are trying to solve here is the reuse of common behaviors across test classes avoiding coding duplication and centralizing these actions at one point. The application of a Base test class in OO programming languages is applied using inheritance.

Base Test Class Without this approach, we have code duplicated related to: ○ pre-condition ○ post-condition ○ any shared method TEST 1 TEST 2 TEST 3 pre-condition post-condition pre-condition post-condition pre-condition post-condition

Base Test Class With this approach, we have: ○ the smart use of inheritance ○ an easy way to add more test ○ flexible creation of test suites BASE TEST CLASS TEST 1 TEST 2 TEST 3 browser initialization/close open/close database, logs connect/disconnect servers login/logout app

Examples without the usage of Base Test class ○ FirstPageCheckTest with the usage of Base Test class ○ BaseTestWeb ○ FirstPageCheckTest

Builder and Fluent Interface

Builder This pattern tries to manage the construction process of an object using its constructor in fluent methods. Regular class example public class Product { private final String name; private final String description; private final BigDecimal price; public Product(String name, String description, BigDecimal price) { this.name = name; this.description = description; this.price = price; } }

Builder public class ProductBuilder { private String name; private String description; private BigDecimal price; public ProductBuilder name(String name) { this.name = name; return this; } public ProductBuilder description(String description) { this.description = description; return this; } public ProductBuilder price(BigDecimal price) { this.price = price; return this; } public Product build() { return new Product(name, description, price); } } Builder construction ● All methods return the class (this) ● The build() method call the constructor

Fluent Interface This pattern tries to provide a readable fluent API over a specific domain. The domain can include more than one class. public class AmazonPage { public AmazonPage selectDepartment(Departament departament) { // some magic here return this; } public AmazonPage search(String term) { // some magic here return this; } } class FluentInterfaceTest { @Test void searchInAllDepartaments() { AmazonPage amazonPage = new AmazonPage(); amazonPage.search("Kindle Fire"); } @Test void searchOnComputers() { AmazonPage amazonPage = new AmazonPage(); amazonPage.selectDepartment(Department.BOOKS) .search("Effective Java"); } } Fluent interface Usage

Examples builder implementation ○ Product ○ ProductBuilder ○ ProductBuilderTest fluent interface ○ AmazonPage ○ Department ○ FluentInterfaceTest

Factory

Factory This creational pattern enables the creation of objects without exposing the internal logic. A good test example is the creation of different browser instances. BROWSER FACTORY FIREFOX SAFARI EDGE CHROME

Factory The basic implementation is done by having specific classes that will create different objects, while the main class is responsible to understand the object type to create it. More information at http://www.eliasnogueira.com/how-to-use-the-factory-design-pattern-to-create-browser-instances-the-simple-approach

Examples browser factory ○ BrowserFactory ○ FactoryTest

Data Generation

Data Generation There are many ways to generate data… The most common are: STATIC/DYNAMIC GENERATION FAKES

Fake Generation Creates an approach to generate non-sensitive data for your test without manually changing the test data in each execution. There’re a lot of tools to create this type of data. Example with Java-Faker Faker faker = new Faker(new Locale("pt-BR")); faker.name().fullName(); faker.address().fullAddress(); faker.internet().emailAddress(); faker.business().creditCardNumber(); faker.date().birthday();

Fake Generation + Data Factory We can use a Fake Generation in a centralized data class that can create data in any condition. public class CreditCardDataFactory { public CreditCard validCreditCard() {} public CreditCard invalidCreditCardNumber() {} public CreditCard invalidMonth() {} public CreditCard invalidYear() {} public CreditCard invalidCcv() {} }

Examples data factory ○ CreditCardDataFactory ○ DataFactoryTest

Static Generation When the data cause different behaviors in your application. A Static approach can be achieved by implementing any data approach like: ○ Class ○ CSV | JSON | TXT | YML ○ Database ○ Mock

Changeless data It’s a set of common data used across the project consisting of a final class containing constants. The changeless data (constants) will be used in different classes and the advantage is the single point of change. We can have multiple classes shaping the different data requirements.

Examples Changeless data ○ AssertionData ○ BrowserData ○ GeneralData

Data Driven It is one of the Static data generation types. It consists of using different data in the same test, where the data changes, not the test. Different test libraries have this approach available. Most of them consist of the data hard-coded in a test class. More info about JUnit 5 data driven methods at: https://junit.org/junit5/docs/current/user-guide/#writing-tests-parameterized-tests @Override public Stream extends Arguments> provideArguments(ExtensionContext extensionContext) { return Stream.of( arguments("Micro SD Card 16Gb", new BigDecimal("6.09")), arguments("JBL GO 2", new BigDecimal("22.37")), arguments("iPad Air Case", new BigDecimal("14.99")) ); }

Examples data driven ○ CreditCardDataDriven ○ DataDrivenTest

Dynamic Generation The Dynamic approach can be implemented according to your context. Used to remove the maintenance of test data. Example: ○ Queries in a database ○ Consume data from an API

Configuration Management

Configuration Management It provides a way to set different values for a running application without the necessity of re-compile or re-run it. Normally, this approach accepts dynamic values injection through environment variables or by modifying a configuration file.

Examples configuration management ○ Configuration ○ ConfigurationManager ○ config.properties ○ WebConfigTest

Logs and Reports

Logs and Reports We can generate logs and reports in different ways, but it’s important to have both in your test project whatever the tools you will choose for this. TEST REPORT EXCEPTIONS AND BASIC LOGS

Exceptions and basic logs By using any log strategy, saving a log file, we can understand the common errors that occurred during the test execution. These errors can be of: ○ assertion errors ○ timeout exceptions ○ locator exception ○ an exception on your architecture You can also log basic info to know some action you are doing in the code.

Examples logs ○ log4j2.properties ○ CreditCardDataFactory ○ 3-design-patterns-arch-decision.log file generated in your user folder

Test Report Do not matter if you will generate the test report in any style (below): the most important thing is to have one to satisfy your requirements. We can have it reported as: ○ Gherkin style (readable by humans) ○ xUnit style (readable by CI/CD tools) ○ HTML (readable by humans) ○ any other style like XML, JSON, etc…

Examples reports ○ allure.properties ○ Allure configuration placed on pom.xml ○ auto-generated xUnit XML reports at target/surefire-reports

Thanks! SCAN ME You can follow me on Twitter @eliasnogueira and find the practical examples of this presentation. Be sure to simulate the examples in the code! github.com/eliasnogueira/3-design-patters-arch-decisions