Writing unit tests is easy with Dlang. The unittest
block allows you to start writing tests and to be productive with no special setup.
Unfortunately the assert expresion does not help you to write expressive asserts, and in case of a failure it's hard to find why an assert failed. The fluent-asserts
library allows you to more naturally specify the expected outcome of a TDD or BDD-style test.
-
Add the DUB dependency: https://code.dlang.org/packages/fluent-asserts
-
Import it:
import fluent.asserts;
- Use it:
unittest {
true.should.equal(false).beacause("this is a failing assert");
}
unittest {
Assert.equal(true, false, "this is a failing assert");
}
- Run the tests:
➜ dub test --compiler=ldc2
The library provides the should
template and the Assert
struct.
should
can be used in combination with Uniform Function Call Syntax (UFCS)
auto should(T)(lazy const T testData);
So the following statements are equivalent
testedValue.should.equal(42);
should(testedValue).equal(42);
In addition, the library provides the not
and because
modifiers that allow to improve your asserts.
not
negates the assert condition:
testedValue.should.not.equal(42);
because
allows you to add a custom message:
true.should.equal(false).because("of test reasons");
///will output this message: Because of test reasons, true should equal `false`.
Assert
is a wrapper for the should struct that allows you to use the asserts with a different sintax.
For example, the folowing lines are equivalent:
testedValue.should.equal(42);
Assert.equal(testedValue, 42);
All the asserts that are available using the should
syntax are available with Assert
. If you want to negate the check,
just add not
before the assert name:
Assert.notEqual(testedValue, 42);
You can use fluent asserts with:
MIT. See LICENSE for details.