Generates random test data with a variety of built-in generators.
Supports calculated properties, flexible string generation, and allows for custom property generation.
Provides the ability to decorate the generated output with custom logic.
Construct a property value using just generated values from the same object.
// Given: FirstName and LastName are randomly generated. The email is dynamically constructed.
.Property(s => s.Email).Construct(s => $"{s.FirstName}.{s.LastName}@mycompany.com")
${\color{darkgreen}{String \space templates}}$
Support placeholders for numbers, resources, and file content, replacing them with values from the corresponding list.
Define rules for generating values, each associated with a probability.
// Generates a negative value in the range of [-5, -1) with a probability of 0.1 (10%).
.Property(s => s.Year)
.Range(1,5)
.GenerationRule("NegativeYear", 0.1, _ => Random.Shared.Next(-5, -1))
[!Note]
The probability of using the default generation logic (P<sub>d</sub>) — when no specific generation rules apply — is calculated as: P<sub>d</sub> = 1 - ΣP<sub>i</sub>.
Where P<sub>i</sub> represents the probability of each individual generation rule.
${\color{darkgreen}{Nullable \space rule}}$
Defines the probability of assigning a null value.
[!Note]
The property type must be either nullable (T?) or a reference type with nullable annotations enabled (?).
// Precondition
class Student
{
public string? FirstName {get; set; }
public string LastName {get; set; }
}
// Great job :)
.Property(s => s.FirstName)
.Template("[file:firstnames.txt]")
.Nullable(0.25)
// Will throw an exception :(
.Property(s => s.FirstName)
.Template("[file:lastnames.txt]")
.Nullable(0.25)
${\color{darkgreen}{Custom \space generators}}$
// A custom generator should inherit from `GeneratorBase<T>`
public class PhoneGenerator : GeneratorBase<string>
{
private const char SpecialSymbol = '#';
public override string CreateRandomValue(Property property)
{
var mask = property.GetValueRule("PhoneMask") ?? "### ### ###";
var builder = new StringBuilder();
Random random = GetRandomInstance(property);
foreach (var c in mask.ToString()!)
builder.Append(c != SpecialSymbol ? c : random.Next(0, 10).ToString());
return builder.ToString();
}
}
// Usage
.Property(s => s.Phone)
.UseGenerator(new PhoneGenerator())
.ValueRule("PhoneMask", "## ## ## ##")
