/**
* Chooses a char between min and max, bounds inclusive and chars distributed according to the
* underlying random number generator.
*
* <p>Note: min and max are internally swapped if min > max.
*
* @param min lower bound
* @param max upper bound
* @return A new char generator
*/
static Gen<Character> choose(char min, char max) {
if (min == max) {
return ignored -> min;
} else {
return random -> (char) (int) Gen.choose((int) min, (int) max).apply(random);
}
}
@Test
public void shouldFlatMapArbitrary() {
final Arbitrary<Integer> arbitraryInt = size -> Gen.choose(-size, size);
final Arbitrary<BinaryTree<Integer>> arbitraryTree =
arbitraryInt.flatMap(i -> new ArbitraryBinaryTree(-i, i));
assertThat(arbitraryTree.apply(0).apply(new Random())).isNotNull();
}
@Override
public Gen<BinaryTree<Integer>> apply(int n) {
return random ->
Gen.choose(minValue, maxValue)
.flatMap(
value -> {
if (n == 0) {
return Gen.of(BinaryTree.leaf(value));
} else {
return Gen.frequency(
Tuple.of(1, Gen.of(BinaryTree.leaf(value))),
Tuple.of(
4,
Gen.of(
BinaryTree.branch(
apply(n / 2).apply(random),
value,
apply(n / 2).apply(random)))));
}
})
.apply(random);
}
@Test
public void shouldMapArbitrary() {
final Arbitrary<Integer> arbitraryInt = size -> Gen.choose(-size, size);
final Arbitrary<BinaryTree<Integer>> arbitraryTree = arbitraryInt.map(BinaryTree::leaf);
assertThat(arbitraryTree.apply(0).apply(new Random())).isNotNull();
}
@Test
public void shouldCreateArbitraryString() {
final Arbitrary<String> arbitrary = Arbitrary.string(Gen.choose('a', 'z'));
final String actual = arbitrary.apply(10).apply(new Random());
assertThat(actual).isNotNull();
}