The code above is a straightforward test of our helper function fromDatabase, which works in the following way:

The forAll will generate a lot of Product entities using the generator (Line 3).

From each entity, a list of “rows” is constructed as they would appear in the database (Line 4).

These constructed rows are given to the fromDatabase function (Line 5).

The returned Option must then contain the generated value.

Because we construct the input for the function from a valid generated instance, the function must always return valid output.