@Freeze

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.

How to Use

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:

Java

@AllArgsConstructor
@Getter
public class ValueContainer {
    private final String value;
}

Kotlin

class ValueContainer(val value: String)

Java

@ParameterizedTest
@AutoSource
void testMethod(@Freeze String arg1, String arg2, ValueContainer arg3) {
    assertEquals(arg1, arg2);
    assertEquals(arg1, arg3.getValue());
}

Kotlin

@ParameterizedTest
@AutoSource
fun testMethod(@Freeze arg1: String, arg2: String, arg3: ValueContainer) {
    assertEquals(arg1, arg2)
    assertEquals(arg1, arg3.value)
}

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.

Benefits

1. Consistency: @Freeze ensures that certain values stay constant, making it easier to verify relations between different parameters in your tests.
2. Simpler Test Logic: Reusing a fixed value across multiple parameters simplifies your test logic and makes your tests easier to read and maintain.
3. Control Over Randomness: While @AutoSource provides the benefit of random value generation, @Freeze gives 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.