MANAGING TEST DATA @eliasnogueira

ELIAS NOGUEIRA Senior Principal Software Engineer Brazil Oracle Ace Java Magazine NL Editor Java Champion

THE PROBLEM WE WANT TO SOLVE

hard troubleshooting data without meaning is hard to understand [INFO ] 2023-03-05 18:03:54.081 [main] Person - model1 - Person[ name=etSfgOGRQA, surname=USwRiZSZnKdYAlYBNYJVcDFRgmSLfO, [email protected], age=1, address=XmcWoqivEzSoUwEksGNjlzrjUmWKKCIDOTsDnPAlHPQMJaWYzt] [INFO ] 2023-03-05 18:03:54.090 [main] Person - model1 - Person[ name=rtxhUtqzhV, surname=yruPCovuOMXrXUKqZnkxgrDIsdUWMY, [email protected], age=60, address=tFlnvWupyHnnHkAzuHAFzmRbrFUjwViqHSUEDjqCWfQdjKhBFM]

hard troubleshooting data without meaning is hard to understand [INFO ] 2023-03-05 18:03:54.081 [main] Person - model1 - Person[ name=etSfgOGRQA, surname=USwRiZSZnKdYAlYBNYJVcDFRgmSLfO, [email protected], age=1, address=XmcWoqivEzSoUwEksGNjlzrjUmWKKCIDOTsDnPAlHPQMJaWYzt]

not prioritized data requirements data must match any rule or restriction [INFO ] 2023-03-05 18:03:54.081 [main] Person - model1 - Person[ name=etSfgOGRQA, surname=USwRiZSZnKdYAlYBNYJVcDFRgmSLfO, [email protected], age=1, address=XmcWoqivEzSoUwEksGNjlzrjUmWKKCIDOTsDnPAlHPQMJaWYzt] probably will make a test fail

no patterns for data generation we must avoid code duplication private static Person personToCreate() { Person person = new Person( "Test user", "Surname", "[email protected]", 18, "User address, 50 – Brühl" ); return person; } multiple methods to generate the same data can (wrongly) exist

hard troubleshooting not prioritized data requirements no patterns for data generation - possibly fixed/data repetition

HOW TO SOLVE THE PROBLEM?

define a way to generate data use a specialized tool understand the data requirements know the testing library support for data 1⃣ 2⃣ 3⃣ 4⃣

DEFINE A WAY TO GENERATE DATA

There are some approaches to generating data - Combining Object Mother and Fluent Builder for the Ultimate Test Data Factory - Test Data Builders and Object Mother: another look - Writing Clean Tests – New Considered Harmful - Test Data Builders: an alternative to the Object Mother pattern define a way to generate data

common approaches builder pattern, in the Model objects factory pattern to generate the data tool for dynamic data generation test data factory

model object @Data @Builder @EqualsAndHashCode public class Simulation { @JsonIgnore private Long id; private String name; private String cpf; private String email; private BigDecimal amount; private Integer installments; private Boolean insurance; }

builder pattern var simulation = Simulation.builder() .cpf("94827495037") .name("John Doe") .email("[email protected]") .amount(new BigDecimal("1000")) .installments(5) .insurance(true) .build();

factory pattern public final class SimulationDataFactory { public static Simulation createSimulation() { return Simulation.builder().cpf("94827495037") .name("John Doe").email("[email protected]") .amount(new BigDecimal("1000")).installments(5) .insurance(true).build(); } }

Talk is cheap. Show me the code. Linus Torvalds

USE A SPECIALIZED TOOL

https://www.slideshare.net/JaapCoomans/fairies-fakers-and-factories-boost-your-tests-with-better-test-data

use a specialized tool Tool What it does Comment Easy Random Generate random data based on Java beans For a long time not updated (3 years) Uses JavaFaker for specialized data jFairy Generate data based on different aspects Uses Apache Commons library, IBAJ4J, and custom YAML files Instancio Creates and populates objects Uses a custom solution for data generation DataFaker Generate data based on YAML and random code Fork from JavaFaker with a more active community

datafaker Faker faker = new Faker(Locale.GERMAN); faker.name().fullName(); // Freiherrin Amar von Lienshöft faker.finance().iban("DE"); // DE37941528189220696520 faker.internet().emailAddress(); // [email protected] faker.expression("#{date.birthday ‘yy MM dd hh:mm:ss'}"); // 78 10 08 10:04:34

test data factory public final class SimulationDataFactory { public static Simulation createSimulation() { return Simulation.builder() .cpf("94827495037") .name("John Doe") .email(("[email protected]") .amount(new BigDecimal("1000")) .installments(5) .insurance(true) .build(); } } Combination of builder + factory

test data factory public final class SimulationDataFactory { public static Simulation createSimulation() { return Simulation.builder() .cpf(faker.cpf().valid()) .name(faker.name().fullName()) .email(faker.internet().emailAddress()) .amount(new BigDecimal(faker.number().numberBetween(1000, 40000))) .installments(faker.number().numberBetween(2, 48)) .insurance(faker.bool().bool()) .build(); } } Combination of builder + factory + tool

Talk is cheap. Show me the code. Linus Torvalds

UNDERSTAND THE DATA REQUIREMENTS

understand the data requirements When we have data requirements to follow… @Min(value = 1000, message = "Amount must be equal or greater than $ 1.000") @Max(value = 40000, message = "Amount must be equal or less than than $ 40.000") private BigDecimal amount; @Min(value = 2, message = "Installments must be equal or greater than 2") @Max(value = 48, message = "Installments must be equal or less than 48") private Integer installments;

public final class SimulationDataFactory { public static Simulation createSimulation() { return Simulation.builder() .cpf(faker.cpf().valid()) .name(faker.name().fullName()) .email(faker.internet().emailAddress()) .amount(new BigDecimal(faker.number().numberBetween(1000, 40000))) .installments(faker.number().numberBetween(2, 48)) .insurance(faker.bool().bool()).build(); } } We must generate the data based on that conditions understand the data requirements

Talk is cheap. Show me the code. Linus Torvalds

KNOW THE TESTING LIBRARY SUPPORT FOR DATA

JUnit 5 data driven Value Source Internal Method Source External Method Source Argument Provider CSV Provider

Value Source JUnit 5 data driven class JUnitValueSourceTest { private static final int VALUE = 7; @DisplayName("Values are greater than or equals to") @ParameterizedTest(name = "{0} is greater than or equals to " + VALUE) @ValueSource(ints = {7, 10, 12, 40}) void valueSourceExample(int value) { assertThat(value).isGreaterThanOrEqualTo(VALUE); } }

Internal Method Source JUnit 5 data driven class JUnitInternalMethodSourceTest { @DisplayName("All products should be cheap") @ParameterizedTest(name = "product ''{0}'' of amount ${1} is cheap") @MethodSource("cheapProducts") void cheapProducts(String product, BigDecimal amount) { final BigDecimal maximumPrice = new BigDecimal("30.0"); assertThat(product).isNotEmpty(); assertThat(amount).isLessThanOrEqualTo(maximumPrice); } static Stream cheapProducts() { 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")) ); } }

JUnit 5 data driven class JUnitExternalMethodSourceTest { private final String CHEAP_PRODUCTS = "com.eliasnogueira.datadriven.JUnitExternalData#cheapProducts"; @ParameterizedTest(name = "product ''{0}'' of amount ${1} is cheap") @MethodSource(value = CHEAP_PRODUCTS) void cheapProducts(String product, BigDecimal amount) { // test goes here } public class JUnitExternalData { public static Stream cheapProducts() { 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")) ); } External Method Source

Argument Provider JUnit 5 data driven class JUnitArgumentProviderTest { private static final String MAXIMUM_PRICE = "30.0"; @DisplayName("Products should not exceed the maximum price") @ParameterizedTest(name = "product ''{0}'' of amount ${1} does not exceeds $" + MAXIMUM_PRICE) @ArgumentsSource(ProductsDataArgumentProvider.class) void cheapProducts(String product, BigDecimal amount) { assertThat(product).isNotEmpty(); assertThat(amount).isLessThanOrEqualTo(new BigDecimal(MAXIMUM_PRICE)); } } public class ProductsDataArgumentProvider implements ArgumentsProvider { @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")) ); } }

CSV Provider JUnit 5 data driven class JUnitCSVSourceTest { private static final String MAXIMUM_PRICE = "30.0"; @DisplayName("Products should not exceed the maximum price") @ParameterizedTest(name = "product ''{0}'' of amount ${1} does not exceeds $" + MAXIMUM_PRICE) @CsvFileSource(resources = "/products.csv", numLinesToSkip = 1) void productsLassThan(String product, BigDecimal amount) { assertThat(product).isNotEmpty(); assertThat(amount).isLessThanOrEqualTo(new BigDecimal(MAXIMUM_PRICE)); } } product,amount Micro SD Card 16Gb,6.09 JBL GO 2,22.37 iPad Air Case,14.99 products.csv

Talk is cheap. Show me the code. Linus Torvalds

REFERENCES

JUnit 5 data driven Main project https://github.com/eliasnogueira/manage-testing-data-java • Value Source • Internal Method Source • External Method Source • external method source data class • Argument Provider • argument provider data class • CSV Provider • csv file

Main project https://github.com/eliasnogueira/credit-api/tree/manage-data • TestData Factory • Argument provider for edge cases • Tests test data factory

THANK YOU! @eliasnogueira https://github.com/eliasnogueira/public-speaking