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package au.id.zancanaro.javacheck;
import au.id.zancanaro.javacheck.annotations.DataSource;
import au.id.zancanaro.javacheck.annotations.Property;
import au.id.zancanaro.javacheck.junit.Properties;
import org.junit.runner.RunWith;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import static au.id.zancanaro.javacheck.Generators.longInteger;
import static au.id.zancanaro.javacheck.Generators.oneOf;
import static org.junit.Assert.assertEquals;
@RunWith(Properties.class)
public class SetFunctorRulesTest {
@DataSource
public static Generator<Function<Long, Long>> integerFunction =
oneOf(
longInteger().map(SetFunctorRulesTest::plusI),
longInteger().map(SetFunctorRulesTest::timesI),
longInteger().map(SetFunctorRulesTest::constantlyI));
@Property
public void mappingCompositionsWithStreams(
Set<Long> list,
Function<Long, Long> f,
Function<Long, Long> g) {
Set<Long> left = list.stream()
.map(g)
.map(f)
.collect(Collectors.toSet());
Set<Long> right = list.stream()
.map(f.compose(g))
.collect(Collectors.toSet());
assertEquals(left, right);
}
@Property
public void mappingCompositionsWithIntermediateList(
Set<Long> list,
Function<Long, Long> f,
Function<Long, Long> g) {
Set<Long> intermediate = list.stream().map(g).collect(Collectors.toSet());
Set<Long> left = intermediate.stream().map(f).collect(Collectors.toSet());
Set<Long> right = list.stream()
.map(f.compose(g))
.collect(Collectors.toSet());
assertEquals(left, right);
}
@Property
public void mapIdentityIsIdentity(Set<Long> list) {
Set<Long> mapped = list.stream().map(x -> x).collect(Collectors.toSet());
assertEquals(list, mapped);
}
private static Function<Long, Long> plusI(final long i) {
return new Function<Long, Long>() {
@Override
public Long apply(Long integer) {
return i + integer;
}
@Override
public String toString() {
return "x -> x + " + i;
}
};
}
private static Function<Long, Long> timesI(final long i) {
return new Function<Long, Long>() {
@Override
public Long apply(Long integer) {
return i * integer;
}
@Override
public String toString() {
return "x -> x * " + i;
}
};
}
private static Function<Long, Long> constantlyI(final long i) {
return new Function<Long, Long>() {
@Override
public Long apply(Long integer) {
return i;
}
@Override
public String toString() {
return "x -> " + i;
}
};
}
}
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