Skip to content

Fixes #401. Add fj.test.Gen.sequence(Validation<E, Gen<A>>). #402

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
tonymorris merged 1 commit into from
Jul 21, 2020
Merged

Fixes #401. Add fj.test.Gen.sequence(Validation<E, Gen<A>>). #402

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 14 additions & 0 deletions quickcheck/src/main/java/fj/test/Gen.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
import fj.data.List;
import fj.data.Option;
import fj.data.Stream;
import fj.data.Validation;
import fj.function.Effect1;

import static fj.Bottom.error;
Expand Down Expand Up @@ -319,6 +320,19 @@ public static <A> Gen<List<A>> sequenceN(final int n, final Gen<A> g) {
return sequence(replicate(n, g));
}

/**
* Transform a validation for a generator into a generator of validations: if the given validation is a failure, the
* generator produces that failure value; if the given validation is a success, the generator produces success values.
*
* @param gv The validation for a generator.
* @param <A> the type of the value
* @param <E> the type of the failure
* @return if the given validation is a failure, the generator produces that failure value; if the given validation is a success, the generator produces success values.
*/
public static <E, A> Gen<Validation<E, A>> sequence(final Validation<E, Gen<A>> gv) {
return gen(i -> r -> gv.map(g -> g.gen(i, r)));
}

/**
* Constructs a generator that can access its construction arguments &mdash; size and random
* generator.
Expand Down
19 changes: 19 additions & 0 deletions quickcheck/src/test/java/fj/test/GenTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,17 +1,27 @@
package fj.test;

import fj.Equal;
import fj.data.List;
import fj.data.NonEmptyList;
import fj.data.Option;
import fj.data.Stream;
import fj.data.Validation;
import fj.function.Effect1;
import org.junit.Test;

import static fj.Ord.charOrd;
import static fj.data.List.list;
import static fj.data.List.range;
import static fj.data.NonEmptyList.nel;
import static fj.data.Option.somes;
import static fj.data.Validation.fail;
import static fj.data.Validation.success;
import static fj.test.Gen.combinationOf;
import static fj.test.Gen.listOf;
import static fj.test.Gen.permutationOf;
import static fj.test.Gen.pickOne;
import static fj.test.Gen.selectionOf;
import static fj.test.Gen.sequence;
import static fj.test.Gen.streamOf;
import static fj.test.Gen.wordOf;
import static fj.test.Rand.standard;
Expand Down Expand Up @@ -187,6 +197,15 @@ public void testStreamOf() {
});
}

@Test
public void testSequenceValidation() {
final Gen<List<Validation<NonEmptyList<Exception>, Character>>> success = listOf(sequence(success(pickOne(AS))), 4);
testPick(100, success, list -> assertEquals(list.length(),somes(list.map(v -> Option.sequence(v.map(c -> AS.elementIndex(Equal.anyEqual(), c))))).length()));

final Gen<List<Validation<NonEmptyList<Exception>, Gen<Character>>>> failure = listOf(sequence(fail(nel(new Exception()))), 4);
testPick(100, failure, list -> assertTrue(list.forall(a -> a.isFail())));
}

private static <A> void testPick(int n, Gen<List<A>> instance, Effect1<List<A>> test) {
range(0, n).map(ignore -> instance.gen(0, standard)).foreachDoEffect(test);
}
Expand Down