AutoParams is an arbitrary test data generator designed for parameterized tests in Java, drawing inspiration from AutoFixture.
Manually configuring test data can be cumbersome, especially when certain data is necessary but not critical to a specific test. AutoParams eliminates this hassle by automatically generating test arguments for your parameterized methods, allowing you to focus more on your domain-specific requirements.
Using AutoParams is straightforward. Simply annotate your parameterized test method with the @AutoSource annotation, in the same way you would use the @ValueSource or @CsvSource annotations. Once this is done, AutoParams takes care of generating appropriate test arguments automatically.
@ParameterizedTest
@AutoSource
void parameterizedTest(int a, int b) {
Calculator sut = new Calculator();
int actual = sut.add(a, b);
assertEquals(a + b, actual);
}In the example above, the automatic generation of test data by AutoParams can potentially eliminate the need for triangulation in tests, streamlining the testing process.
AutoParams also simplifies the writing of test setup code. For instance, if you need to generate multiple review entities for a single product, you can effortlessly accomplish this using the @Freeze annotation.
@AllArgsConstructor
@Getter
public class Product {
private final UUID id;
private final String name;
private final BigDecimal priceAmount;
}@AllArgsConstructor
@Getter
public class Review {
private final UUId id;
private final Product product;
private final String comment;
}@ParameterizedTest
@AutoSource
void testMethod(@Freeze Product product, Review[] reviews) {
for (Review review : reviews) {
assertSame(product, review.getProduct());
}
}That's cool!
- JDK 1.8 or higher
For Maven, you can add the following dependency to your pom.xml:
<dependency>
<groupId>io.github.autoparams</groupId>
<artifactId>autoparams</artifactId>
<version>8.3.0</version>
</dependency>For Gradle, use:
testImplementation 'io.github.autoparams:autoparams:8.3.0'AutoParams effortlessly generates test arguments for primitive data types, such as booleans, integers, and floats.
@ParameterizedTest
@AutoSource
void testMethod(boolean x1, byte x2, int x3, long x4, float x5, double x6, char x7) {
}The framework also provides test arguments in the form of simple objects like Strings, UUIDs, and BigIntegers.
@ParameterizedTest
@AutoSource
void testMethod(String x1, UUID x2, BigInteger x3) {
}Enum types are seamlessly integrated as well. AutoParams will randomly select values from the enum for test arguments.
public enum Day {
SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
THURSDAY, FRIDAY, SATURDAY
}@ParameterizedTest
@AutoSource
void testMethod(Day arg) {
}For more complicated objects, AutoParams utilizes the public constructor with arbitrary arguments to generate test data. If the class has multiple public constructors, the framework will select the one with the fewest parameters to initialize the object.
@AllArgsConstructor
@Getter
public class ComplexObject {
private final int value1;
private final String value2;
}@ParameterizedTest
@AutoSource
void testMethod(ComplexObject arg) {
}When AutoParams generates objects of complex types, it adheres to the following selection criteria for constructors:
- Priority is given to constructors that are annotated with the
@ConstructorPropertiesannotation. - If no such annotation is present, AutoParams will choose the constructor with the fewest parameters.
@Getter
public class ComplexObject {
private final int value1;
private final String value2;
private final UUID value3;
@ConstructorProperties({"value1", "value2, value3"})
public ComplexObject(int value1, String value2, UUID value3) {
this.value1 = value1;
this.value2 = value2;
this.value3 = value3;
}
@ConstructorProperties({"value1", "value2"})
public ComplexObject(int value1, String value2) {
this(value1, value2, null);
}
public ComplexObject(int value1) {
this(value1, null, null);
}
}@ParameterizedTest
@AutoSource
void testMethod(ComplexObject arg) {
assertNotNull(object.getValue2());
assertNull(object.getValue3());
}AutoParams is capable of generating objects of generic types, adhering to its constructor selection policy. When dealing with generic types, AutoParams employs a public constructor with arbitrary arguments for object creation. If multiple public constructors are available, the framework opts for the one with the fewest parameters.
@AllArgsConstructor
@Getter
public class GenericObject<T1, T2> {
private final T1 value1;
private final T2 value2;
}@ParameterizedTest
@AutoSource
void testMethod(
GenericObject<String, ComplexObject> arg1,
GenericObject<UUID, GenericObject<String, ComplexObject>> arg2) {
}AutoParams offers extensive support for various collection types, enhancing its utility for more complex testing scenarios.
AutoParams automatically generates array instances, each containing three elements by default.
@ParameterizedTest
@AutoSource
void testMethod(int[] array1, String[] array2) {
}Both the List<E> interface and the ArrayList<E> class are supported. AutoParams generates list objects that contain a few elements.
@ParameterizedTest
@AutoSource
void testMethod(List<String> list, ArrayList<UUID> arrayList) {
}AutoParams also supports the Set<E> interface and the HashSet<E> class, generating set objects that contain a few elements.
@ParameterizedTest
@AutoSource
void testMethod(Set<String> set, HashSet<UUID> hashSet) {
}Support extends to the Map<K, V> interface and the HashMap<K, V> class as well. AutoParams generates map objects containing a few key-value pairs.
@ParameterizedTest
@AutoSource
void testMethod(Map<String, ComplexObject> map, HashMap<UUID, ComplexObject> hashMap) {
}This comprehensive support for collection types makes AutoParams an exceptionally versatile tool for generating test data, accommodating a wide variety of data structures to ensure thorough testing.
AutoParams extends its versatility by offering support for various types of stream interfaces, further broadening your testing capabilities.
AutoParams supports the generic Stream<T> interface and generates stream objects containing a few elements.
@ParameterizedTest
@AutoSource
void testMethod(Stream<ComplexObject> stream) {
}AutoParams also accommodates stream interfaces that are specific to primitive types, such as IntStream, LongStream, and DoubleStream.
@ParameterizedTest
@AutoSource
void testMethod(IntStream arg1, LongStream arg2, DoubleStream arg3) {
}This added layer of support for stream types allows AutoParams to be a comprehensive solution for generating test data across a wide range of data structures and types, making your testing more robust and efficient.
The @Repeat annotation in AutoParams provides you with a straightforward way to repeat a unit test multiple times, each time with newly generated, arbitrary test data. This can be particularly useful when you want to ensure that a piece of code functions as expected across a variety of input conditions.
To use the @Repeat feature, you'll need to attach the @Repeat annotation alongside the @AutoSource annotation on your parameterized test method. The repeat property of the @Repeat annotation takes an integer value, specifying the number of times the test should be repeated.
Here's an example:
@ParameterizedTest
@AutoSource
@Repeat(10)
void testMethod(int a, int b) {
// This test method will be executed ten times with different sets of 'a' and 'b' each time.
Calculator sut = new Calculator();
int actual = sut.add(a, b);
assertEquals(a + b, actual);
}In the example above, the test method testMethod will run ten times. Each run will have a new set of randomly generated values for a and b, thanks to the @AutoSource annotation. The @Repeat(10) ensures that this cycle happens ten times, enhancing the test coverage.
- Diverse Test Data: The
@Repeatfeature allows you to test your methods across a wider range of automatically generated input values. - Reduced Manual Effort: There's no need to manually specify multiple sets of test data or create loops within your tests.
- Increased Test Robustness: Repeating tests multiple times with varying data can uncover edge cases and improve the reliability of your software.
By using the @Repeat feature, you can increase the comprehensiveness and reliability of your test suite with minimal additional effort.
AutoParams provides a @Freeze annotation to let you fix the value of a generated argument. Once an argument is fixed using the @Freeze annotation, @AutoSource will reuse this fixed value for any subsequent parameters of the same type within the same test method.
Simply decorate the parameter in your test method with the @Freeze annotation. This will instruct AutoParams to keep that parameter's value constant while generating new values for other parameters.
Here's an example:
@AllArgsConstructor
@Getter
public class ValueContainer {
private final String value;
}@ParameterizedTest
@AutoSource
void testMethod(@Freeze String arg1, String arg2, ValueContainer arg3) {
assertEquals(arg1, arg2);
assertEquals(arg1, arg3.getValue());
}In the above example, the value of arg1 is fixed by the @Freeze annotation. The test verifies that arg1 is equal to arg2 and also equal to the value property of arg3. As a result, arg1, arg2, and arg3.getValue() will all contain the same string value, thanks to the @Freeze annotation.
- Consistency:
@Freezeensures that certain values stay constant, making it easier to verify relations between different parameters in your tests. - Simpler Test Logic: Reusing a fixed value across multiple parameters simplifies your test logic and makes your tests easier to read and maintain.
- Control Over Randomness: While
@AutoSourceprovides the benefit of random value generation,@Freezegives you control when you need specific values to be consistent throughout a test.
The @Freeze annotation is a powerful feature for scenarios where you need to maintain the consistency of certain test parameters while still benefiting from the randomness and coverage offered by AutoParams.
The @ValueAutoSource annotation combines the capabilities of @ValueSource and @AutoSource, providing a more flexible way to generate test arguments. Specifically, it assigns a predefined value to the first parameter and then generates arbitrary values for the remaining parameters.
To employ the @ValueAutoSource annotation, add it above your test method and specify the values for the first parameter using the attributes like strings, ints, etc., just as you would with @ValueSource.
Here's an example:
@ParameterizedTest
@ValueAutoSource(strings = {"foo"})
void testMethod(String arg1, String arg2) {
assertEquals("foo", arg1);
assertNotEquals(arg1, arg2);
}In this case, arg1 is set to "foo", while arg2 will receive an automatically generated value. The test confirms that arg1 is exactly "foo" and that arg2 is different from arg1.
The @ValueAutoSource annotation is fully compatible with the @Freeze annotation, allowing you to fix certain parameter values while also providing predefined values for others.
Here is how they can work together:
@AllArgsConstructor
@Getter
public class ValueContainer {
private final String value;
}@ParameterizedTest
@ValueAutoSource(strings = {"foo"})
void testMethod(@Freeze String arg1, String arg2, ValueContainer arg3) {
assertEquals("foo", arg2);
assertEquals("foo", arg3.getValue());
}- Combining Fixed and Random Values:
@ValueAutoSourceallows you to specify certain parameter values while letting AutoParams generate random values for others, offering the best of both worlds. - Enhanced Flexibility: This feature grants you more control over test data, making it easier to cover a wide range of scenarios.
- Reduced Test Complexity: By combining the functionalities of
@ValueSourceand@AutoSource, you can simplify your test setup, making it easier to read and maintain.
The @ValueAutoSource annotation is a versatile addition to your testing toolkit, giving you greater control over test data while maintaining the benefits of automated random data generation.
The @CsvAutoSource annotation merges the features of @CsvSource and @AutoSource, providing you with the flexibility to specify CSV-formatted arguments for some parameters while generating random values for the remaining ones.
To use @CsvAutoSource, annotate your test method with it and provide CSV-formatted input values for the initial set of parameters. The remaining parameters will be populated with automatically generated values.
Here's a simple example:
@ParameterizedTest
@CsvAutoSource({"16, foo"})
void testMethod(int arg1, String arg2, String arg3) {
assertEquals(16, arg1);
assertEquals("foo", arg2);
assertNotEquals(arg2, arg3);
}In this example, arg1 is set to 16 and arg2 is set to "foo" based on the provided CSV input. Meanwhile, arg3 will be assigned a randomly generated value. The test verifies that arg3 is different from arg2.
Just like @ValueAutoSource, @CsvAutoSource is fully compatible with the @Freeze annotation, allowing you to lock in values for specific parameters while also defining others via CSV.
Here's how they can work together:
@AllArgsConstructor
@Getter
public class ValueContainer {
private final String value;
}@ParameterizedTest
@CsvAutoSource({"16, foo"})
void testMethod(int arg1, @Freeze String arg2, ValueContainer arg3) {
assertEquals("foo", arg3.getValue());
}- Dual Control: The ability to specify values via CSV for some parameters while allowing automatic random generation for others provides a high level of control over your test data.
- Streamlined Testing: By allowing both manual and automated data input,
@CsvAutoSourcesimplifies the setup of complex tests. - Flexible and Comprehensive: This feature offers you the flexibility to cover a broader range of test scenarios by mixing pre-defined and random values.
The @CsvAutoSource annotation is another versatile tool in your testing suite, adding both precision and coverage to your parameterized tests.
The @MethodAutoSource annotation blends the capabilities of @MethodSource and @AutoSource. This allows you to specify the names of factory methods for the initial set of parameters, while the remaining parameters are automatically populated with arbitrary values.
To employ @MethodAutoSource, annotate your test method with it and specify the factory method that provides the argument values for the initial parameters. AutoParams will generate values for the remaining parameters.
Here's a straightforward example:
@ParameterizedTest
@MethodAutoSource("factoryMethod")
void testMethod(int arg1, String arg2, String arg3) {
assertEquals(16, arg1);
assertEquals("foo", arg2);
assertNotEquals(arg2, arg3);
}
static Stream<Arguments> factoryMethod() {
return Stream.of(Arguments.of(16, "foo"));
}In this instance, arg1 and arg2 are set based on the values provided by the factoryMethod. arg3 will be assigned a randomly generated value, and the test confirms that arg3 is not equal to arg2.
The @MethodAutoSource annotation is also fully compatible with the @Freeze annotation. This lets you lock in values for particular parameters while dynamically populating others through a factory method.
Here's how it works together:
@AllArgsConstructor
@Getter
public class ValueContainer {
private final String value;
}@ParameterizedTest
@MethodAutoSource("factoryMethod")
void testMethod(int arg1, @Freeze String arg2, ValueContainer arg3) {
assertEquals("foo", arg3.getValue());
}
static Stream<Arguments> factoryMethod() {
return Stream.of(Arguments.of(16, "foo"));
}- Customizability: The ability to specify factory methods for some parameters allows for highly tailored test setups.
- Simplicity: With automatic value generation for remaining parameters, @MethodAutoSource alleviates the need for extensive manual data preparation.
- Flexibility: This feature allows you to test a wider range of scenarios by combining pre-defined and random values.
The @MethodAutoSource annotation enriches your testing toolkit, offering a balanced blend of control and randomness in your parameterized tests.
You can constrain the range of generated arbitrary values for certain parameters using the @Min and @Max annotations. These annotations allow you to set minimum and maximum bounds, respectively, ensuring that the generated values fall within the specified range.
To set the range for a parameter, simply annotate it with @Min to define the minimum value and @Max to define the maximum value.
Here's an example:
@ParameterizedTest
@AutoSource
void testMethod(@Min(1) @Max(10) int value) {
assertTrue(value >= 1);
assertTrue(value <= 10);
}In this test, the value parameter will always be an integer between 1 and 10, inclusive.
The @Min and @Max annotations are compatible with the following types:
byteByteshortShortintIntegerlongLongfloatFloatdoubleDouble
- Controlled Randomness: These annotations help you fine-tune the scope of randomness, allowing for more targeted and meaningful tests.
- Reduced Test Flakiness: By constraining the range of values, you reduce the risk of encountering edge cases that could make your tests flaky.
- Enhanced Readability: Using
@Minand@Maxmakes it clear to readers what range of values are being tested, thereby improving the readability and maintainability of your test code.
By using the @Min and @Max annotations in conjunction with @AutoSource, you can achieve a balanced mix of randomness and predictability, making your parameterized tests both versatile and reliable.
The @Customization annotation allows you to tailor the generation of test data according to specific business rules or requirements. This powerful feature integrates seamlessly with the AutoParams framework, offering the flexibility to apply custom logic to your parameterized tests.
Let's consider a Product entity, which has some business rules to follow:
- The listPriceAmount must be greater than or equal to 100
- The listPriceAmount must be less than or equal to 1000
- A 10% discount should be offered, reflected in sellingPriceAmount
@AllArgsConstructor
@Getter
public class Product {
private final UUID id;
private final String name;
private final BigDecimal listPriceAmount;
private final BigDecimal sellingPriceAmount;
}You can implement these rules using the Customizer interface:
public class ProductGenerator extends ObjectGeneratorBase<Product> {
@Override
protected Product generateObject(ObjectQuery query, ResolutionContext context) {
UUID id = context.resolve(UUID.class);
String name = context.resolve(String.class);
ThreadLocalRandom random = ThreadLocalRandom.current();
BigDecimal listPriceAmount = new BigDecimal(random.nextInt(100, 1000 + 1));
BigDecimal sellingPriceAmount = listPriceAmount.multiply(new BigDecimal(0.9));
return new Product(id, name, listPriceAmount, sellingPriceAmount);
}
}Annotate your test method to apply the customization:
@ParameterizedTest
@AutoSource
@Customization(ProductGenerator.class)
void testMethod(Product arg) {
assertTrue(arg.getSellingPriceAmount().compareTo(arg.getListPriceAmount()) < 0);
}You can also create a composite customizer to apply multiple custom rules:
public class DomainCustomizer extends CompositeCustomzer {
public DomainCustomizer() {
super(
new EmailGenerator(),
new UserGenerator(),
new SupplierGenerator(),
new ProductGenerator()
);
}
}And use it like this:
@ParameterizedTest
@AutoSource
@Customization(DomainCustomizer.class)
void testMethod(Email email, User user, Supplier supplier, Product product) {
}If your object follows the JavaBeans spec and has settable properties, you can use InstancePropertyCustomizer:
@Getter
@Setter
public class User {
private Long id;
private String name;
}@ParameterizedTest
@AutoSource
@Customization(InstancePropertyWriter.class)
void testMethod(User user) {
assertNotNull(user.getId());
assertNotNull(user.getName());
}The @Customization annotation can also be applied to individual parameters within a test method. Once applied, the customization will affect all following parameters, unless overridden.
This feature provides a nuanced approach to data generation, enabling highly specialized and context-sensitive test scenarios.
autoparams-mockito is an extension of the AutoParams library that facilitates the creation of mocks for interfaces and abstract classes using Mockito, a popular mocking framework in Java. By integrating these two libraries, you can seamlessly generate mock objects for your tests.
For Maven, you can add the following dependency to your pom.xml:
<dependency>
<groupId>io.github.autoparams</groupId>
<artifactId>autoparams-mockito</artifactId>
<version>8.3.0</version>
</dependency>For Gradle, use:
testImplementation 'io.github.autoparams:autoparams-mockito:8.3.0'Consider a situation where you have an interface that abstracts certain services:
public interface Dependency {
String getName();
}You also have a system that relies on this Dependency interface:
public class SystemUnderTest {
private final Dependency dependency;
public SystemUnderTest(Dependency dependency) {
this.dependency = dependency;
}
public String getMessage() {
return "Hello " + dependency.getName();
}
}To generate mock objects for interfaces or abstract classes, the autoparams-mockito extension provides the MockitoCustomizer. When you decorate your test method with @Customization(MockitoCustomizer.class), the @AutoSource annotation will employ Mockito to create mock values for the specified parameters.
Here's how you can apply this in practice:
@ParameterizedTest
@AutoSource
@Customization(MockitoCustomizer.class)
void testUsingMockito(@Freeze Dependency stub, SystemUnderTest sut) {
when(stub.getName()).thenReturn("World");
assertEquals("Hello World", sut.getMessage());
}In the above example:
- The
stubargument is a mock generated by Mockito, thanks to theMockitoCustomizer. - The
@Freezeannotation ensures that this mock object (stub) is reused as a parameter for the construction of theSystemUnderTestobject (sut).
This integration simplifies the creation of mock objects for parameterized tests, making testing more efficient and straightforward.
autoparams-lombok is an extension for the AutoParams library that makes it easier to work with Project Lombok, a library that reduces boilerplate code in Java applications.
For Maven, you can add the following dependency to your pom.xml:
<dependency>
<groupId>io.github.autoparams</groupId>
<artifactId>autoparams-lombok</artifactId>
<version>8.3.0</version>
</dependency>For Gradle, use:
testImplementation 'io.github.autoparams:autoparams-lombok:8.3.0'When working with @Builder annotation, you can use the BuilderCustomizer to facilitate generating arbitrary objects for your tests. Here's an example:
Suppose you have a User class like so:
import lombok.Builder;
import lombok.Getter;
@Builder
@Getter
public class User {
private Long id;
private String name;
private String email;
}You can use BuilderCustomizer to create objects of type User for your tests:
@ParameterizedTest
@AutoSource
@Customization(BuilderCustomizer.class)
void testMethod(User user) {
assertThat(arg.getId()).isNotNull();
assertThat(arg.getName()).isNotNull();
assertThat(arg.getEmail()).isNotNull();
}If you've customized the builder method names using builderMethodName and buildMethodName in your Lombok @Builder, you'll need to create a subclass of BuilderCustomizer to handle the custom names:
import lombok.Builder;
import lombok.Getter;
@Builder(builderMethodName = "getBuilder", buildMethodName = "createUser")
@Getter
public class User {
private Long id;
private String name;
private String email;
}Here's how you can extend BuilderCustomizer:
public class UserBuilderCustomizer extends BuilderCustomizer {
public UserBuilderCustomizer() {
super("getBuilder", "createUser");
}
}Now, you can use your customized UserBuilderCustomizer in your tests:
@ParameterizedTest
@AutoSource
@Customization(UserBuilderCustomizer.class)
void testMethod(User user) {
assertThat(arg.getId()).isNotNull();
assertThat(arg.getName()).isNotNull();
assertThat(arg.getEmail()).isNotNull();
}This allows you to keep the benefits of using @Builder annotation while gaining the automatic generation capabilities provided by AutoParams.
autoparams-kotlin is an extension designed to simplify and enhance the experience when working with Kotlin.
For Maven, you can add the following dependency to your pom.xml:
<dependency>
<groupId>io.github.autoparams</groupId>
<artifactId>autoparams-kotlin</artifactId>
<version>8.3.0</version>
</dependency>For Gradle, use:
testImplementation 'io.github.autoparams:autoparams-kotlin:8.3.0'Consider the example of a Point data class in Kotlin:
data class Point(val x: Int = 0, val y: Int = 0)In typical test scenarios, you might want to ensure the parameters passed to your test methods aren't just default or predictable values. The autoparams-kotlin extension can assist in such cases.
Below is a demonstration using the @AutoKotlinSource annotation provided by autoparams-kotlin. This annotation automatically generates random parameters for your test methods:
@ParameterizedTest
@AutoKotlinSource
fun testMethod(point: Point) {
assertThat(point.x).isNotEqualTo(0)
assertThat(point.y).isNotEqualTo(0)
}In this example, the testMethod doesn't receive a hardcoded Point object. Instead, thanks to the @AutoKotlinSource annotation, a randomized Point object is passed in, making the test more robust by ensuring it isn't biased by predetermined values.
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