Jqwik中结合@ForAll、@Provide和集合类型正确定义任意生成器

// domain model
public class Name {
  public final String first;
  public final String last;
  public Name(String f, String l) {
    this.first = f;
    this.last = l;
  }
}

// jqwik domain context
public class NameDomain extends DomainContextBase {
  @Provide
  public Arbitrary<Name> arbName() {
    return Combinators.combine(
      Arbitraries.strings().alpha(),
      Arbitraries.strings().alpha()
    ).as(Name::new);
  }
}

// properties test (Initial Attempt)
public class NameProperties {
  @Provide
  @Domain(NameDomain.class) // Problematic placement
  public Arbitrary<Set<String>> namesToParse(
    @ForAll @Size(min = 1, max = 4) Set<Name> names) {
    // ... code here to convert Set<Name> to Set<String>
    // This method is intended to provide Arbitrary<Set<String>>
    return Arbitrjust.just(names.stream()
                                .map(n -> n.first + " " + n.last)
                                .collect(Collectors.toSet()));
  }

  @Property
  public void namesAreParsed(@ForAll("namesToParse") Set<String> names) {
    // ... use the generated Set<String> here
  }
}

// properties test (Corrected @Domain placement)
@Domain(NameDomain.class) // Correct: Applied to the test class
public class NameProperties {
  @Provide
  // @Domain(NameDomain.class) // Incorrect here
  public Arbitrary<Set<String>> namesToParse(
    @ForAll @Size(min = 1, max = 4) Set<Name> names) {
    // ... still problematic, but @Domain is now correctly placed
    return Arbitrjust.just(names.stream()
                                .map(n -> n.first + " " + n.last)
                                .collect(Collectors.toSet()));
  }

  @Property
  public void namesAreParsed(@ForAll("namesToParse") Set<String> names) {
    // ...
  }
}

import net.jqwik.api.*;
import net.jqwik.api.arbitraries.SetArbitrary;
import net.jqwik.api.domains.DomainContextBase;
import java.util.Set;
import java.util.stream.Collectors;

// domain model (unchanged)
public class Name {
  public final String first;
  public final String last;
  public Name(String f, String l) {
    this.first = f;
    this.last = l;
  }
}

// jqwik domain context (unchanged)
public class NameDomain extends DomainContextBase {
  @Provide
  public Arbitrary<Name> arbName() {
    return Combinators.combine(
      Arbitraries.strings().alpha().ofMinLength(1), // Add min length for meaningful names
      Arbitraries.strings().alpha().ofMinLength(1)
    ).as(Name::new);
  }
}

// properties test (Fully optimized)
@Domain(NameDomain.class) // Correct @Domain placement for the test class
public class NameProperties {

  @Provide
  public Arbitrary<Set<String>> namesToParse() {
    // 1. 获取Name类型的任意生成器，Jqwik会从NameDomain中查找
    // 2. 将其转换为Set<Name>的任意生成器，并指定大小范围
    SetArbitrary<Name> namesArbitrary = Arbitraries.defaultFor(Name.class)
                                                    .set().ofMinSize(1).ofMaxSize(4);

    // 3. 对生成的Set<Name>进行映射，将其中的每个Name对象转换为String
    return namesArbitrary.map(nameSet -> nameSet.stream()
                                                .map(n -> n.first + " " + n.last)
                                                .collect(Collectors.toSet()));
  }

  @Property
  public void namesAreParsed(@ForAll("namesToParse") Set<String> names) {
    // 实际的解析逻辑和断言
    // System.out.println("Generated names: " + names);
    Assertions.assertNotNull(names);
    Assertions.assertFalse(names.isEmpty());
    Assertions.assertTrue(names.size() >= 1 && names.size() <= 4);
    // 假设我们期望每个字符串都是 "firstName lastName" 的格式
    for (String name : names) {
        Assertions.assertTrue(name.contains(" "));
        String[] parts = name.split(" ");
        Assertions.assertEquals(2, parts.length);
        Assertions.assertFalse(parts[0].isEmpty());
        Assertions.assertFalse(parts[1].isEmpty());
    }
  }
}