exceeds-expectations 0.1.1

exceeds-expectations

exceeds-expectations is an assertion library for the D programming language. It uses the expect(___).to___() style used by Jest and Chai.

Usage

To get started, add exceeds-expectations as a unittest dependency to your project:

configuration "unittest" {
    dependency "exceeds-expectations" version="<current version>"
    stringImportPaths "."
}

ℹ️ The stringImportPaths "." is used by exceeds-expectations to point at the lines of code where an expectation failed.

⚠️ If you run into problems with stringImportPaths ".", try using dflags "-J." instead.

Now you can write your unittests in an easily legible format using convenient assertions.

Examples

Equality & Identity

unittest
{
    Pencil pencil = new Pencil();
    Pencil anotherPencil = cloneObject(pencil);

    expect(anotherPencil).toEqual(pencil);
    expect(anotherPencil).not.toBe(pencil);
}

Floating Point Comparison

unittest
{
    real tempCelsius = 23.0;
    real tempFahrenheit = celsiusToFahrenheit(tempCelsius);

    expect(tempFahrenheit).toApproximatelyEqual(73.4);
}

Arbitrary Predicates

When the method you need isn't in the library... yet 😉

unittest
{
    static bool someConvolutedRequirement(int n)
    {
        return (n < 233 && n >= -48 && n % 2 == 0) || (n > 692 && n < 10_002 && n % 3 == 1);
    }

    int myNumber = 8;

    expect(myNumber).toSatisfy(&someConvolutedRequirement);

    // Or:

    expect(8).toSatisfyAny(
        (n) => n < 233 && n >= -48 && n % 2 == 0,
        (n) => n > 692 && n < 10_002 && n % 3 == 1
    )

    // .toSatisfyAll() is also available
}

Why?

Existing assertion libraries (such as dshould and fluent-asserts) rely on unified function call syntax to achieve their natural, sentence-like syntax. Unfortunately, DCD does not support auto-completions using the UFCS syntax. This means that IDEs cannot automatically suggest assertions for you.

In exceeds-expectations, assertions begin with a call to expect(), which returns an "Expectation" object whose member functions are visible to DCD.