Comparison operations

Equality

Specify.That(Foo, Should.Equal(45));
Specify.That(Foo, Should.Yield(45));

Should.Equal and Should.Yield are equivalent; you can use whichever one is more readable in any given context. Here's an example of Should.Yield.

Reference equality

Specify.That(Foo, Should.ReferTo(Bar));

Inequality

Specify.That(Foo, Should.Be.AtLeast(45));
Specify.That(Foo, Should.Be.AtMost(45));
Specify.That(Foo, Should.Be.Between(45, 48));
Specify.That(Foo, Should.Be.GreaterThan(45));
Specify.That(Foo, Should.Be.GreaterThanOrEqualTo(45));
Specify.That(Foo, Should.Be.InRange(45, 48));
Specify.That(Foo, Should.Be.LessThan(45));
Specify.That(Foo, Should.Be.LessThanOrEqualTo(45));

AtLeast and GreaterThanOrEqualTo are equivalent; use whichever name is more readable. The same goes for AtMost and LessThanOrEqualTo.

Type

Specify.That(Foo, Should.Be.OfType(TComponent));

Specific values

Specify.That(Foo, Should.Be.Assigned);
Specify.That(Foo, Should.Be.Null);
Specify.That(Foo, Should.Be.True);
Specify.That(Foo, Should.Be.False);

Additional options for comparisons

Messages

Specify.That(Frequency, Should.Equal(440), 'Frequency');

Specify.That() takes an optional third parameter, which corresponds directly to the Message parameter in DUnit's CheckEquals() methods. This is a must if you have more than one call to Specify.That() in a single test method.

Negation

Specify.That(Foo, Should.Not.Equal(45));

Everything that supports Should... also supports Should.Not...

Epsilons (ToWithin)

Specify.That(Foo, Should.Equal(45.0)); // default epsilon
Specify.That(Foo, Should.Equal(45.0).ToWithin(0.00001));
Specify.That(Foo, Should.Equal(45.0).Exactly); // no epsilon

Floating-point values are notoriously inexact. DUnitLite lets you specify an "epsilon", a number that specifies how close the values should be to be considered equal.

If you don't specify an epsilon, DUnitLite will call Delphi's SameValue function to provide a reasonable epsilon for you. You can also specify your own epsilon with .ToWithin() or .Exactly.

Future plans

FutureSyntax lists some possible syntax that may be added in future versions.