Class BuilderBehavior

Factories for helper classes that provide useful test patterns for builder types.

Inheritance

System.Object

BuilderBehavior

Namespace: LaunchDarkly.TestHelpers

Assembly: LaunchDarkly.TestHelpers.dll

Syntax

public static class BuilderBehavior : Object

Remarks

These helpers make it easier to provide thorough test coverage of builder types. It is easy when implementing builders to make basic mistakes like not setting the right property in a setter, not enforcing desired constraints, or not copying all the properties in a copy constructor.

The general pattern consists of creating a generic helper for the builder type and the type that it builds, then creating a property helper for each settable property and performing standard assertions with it. Example:

    // This assumes there is a type MyBuilder whose Build method creates an
    // instance of MyType, with properties Height and Weight.

    var tester = BuilderBehavior.For(() => new MyBuilder(), b => b.Build());

    var height = tester.Property(x => x.Height, b => (b, value) => b.Height(value));
    height.AssertDefault(DefaultHeight);
    height.AssertCanSet(72);
    height.AssertSetIsChangedTo(-1, 0); // setter should enforce minimum height of 0

    var weight = tester.Property(x => x.Weight, b => (b, value) => b.Weight(value));
    weight.AssertDefault(DefaultWeight);
    weight.AssertCanSet(200);
    weight.AssertSetIsChangedTo(-1, 0); // setter should enforce minimum weight of 0

It uses Xunit assertion methods.

Methods

For<TBuilder>(Func<TBuilder>)

Provides a generic BuilderBehavior.InternalStateTester<TBuilder> for testing methods of a builder against the builder's own internal state.

Declaration

public static BuilderBehavior.InternalStateTester<TBuilder> For<TBuilder>(Func<TBuilder> constructor)

Parameters

Type	Name	Description
System.Func<TBuilder>	constructor	function that constructs a TBuilder

Returns

Type	Description
BuilderBehavior.InternalStateTester<TBuilder>	an BuilderBehavior.InternalStateTester<TBuilder> instance

Type Parameters

Name	Description
TBuilder	the builder type

Remarks

This can be used in cases where it is not feasible for the test code to actually call the builder's build method, for instance if it has unwanted side effects.

For<TBuilder, TBuilt>(Func<TBuilder>, Func<TBuilder, TBuilt>)

Provides a generic BuilderBehavior.BuildTester<TBuilder, TBuilt> for testing methods of a builder against properties of the type it builds.

Declaration

public static BuilderBehavior.BuildTester<TBuilder, TBuilt> For<TBuilder, TBuilt>(Func<TBuilder> constructor, Func<TBuilder, TBuilt> buildMethod)

Parameters

Type	Name	Description
System.Func<TBuilder>	constructor	function that constructs a TBuilder
System.Func<TBuilder, TBuilt>	buildMethod	function that creates a TBuilt from a TBuilder

Returns

Type	Description
BuilderBehavior.BuildTester<TBuilder, TBuilt>	a BuilderBehavior.BuildTester<TBuilder, TBuilt> instance

Type Parameters

Name	Description
TBuilder	the builder type
TBuilt	the type that it builds