The EID program is ready to be released but it does not mean we can not make it even more solid!
Challenge the EID implementation by creating some mutants...
We have designed a robust EID parser making impossible to represent an invalid state.
We reached that, by driving our implementation through the below property:
for all (eid)
parseEID(eid.toString) == eid
Now, let's add a new property that demonstrates that an invalid EID can never be parsed:
for all (validEid)
mutate(eid.toString) == error
We propose to generate a valid EID and mutate its string representation to create an invalid one. For that we will create some mutators.
We have already started to work on it:
// A record that will represent a mutation to make on the EID
private record Mutator(String name, Function1<EID, Gen<String>> func) {
public String mutate(EID eid) {
return func.apply(eid).apply(random);
}
}
// Define mutators here
// This arbitrary will be used to randomly select a mutation to apply to the EID String representation
private static final Arbitrary<Mutator> mutators = Gen.choose((Mutator) null).arbitrary();
@Test
void invalidEIDsCanNotBeParsed() {
Property.def("mutate(eid.toString) == error")
.forAll(validEID, mutators)
.suchThat((eid, mutator) -> EID.parse(mutator.mutate(eid)).isLeft())
.check()
.assertIsSatisfied();
}Read more about it here.
The rules seen earlier still apply:
| Positions | Meaning | Possible values |
|---|---|---|
| 1 | Sex : 1 for Sloubi, 2 for Gagna, 3 for Catact |
1, 2 or 3 |
| 2, 3 | Last two digits of the year of birth (which gives the year to the nearest century) | From 00 to 99 |
| 4, 5, 6 | "Serial number": birth order | From 001 to 999 |
| 7, 8 | control key = complement to 97 of the number formed by the first 6 digits of the EID modulo 97 | From 01 to 97 |
Here is an example of such id:
