fix #4 Add support for Lazy

Author: bosob

README.md

@@ -8,6 +8,8 @@ Adds [jqwik](https://jqwik.net/) arbitraries for [Vavr](https://www.vavr.io/vavr
 - io.vavr.collection.List
 - io.vavr.collection.Set
 
+- io.vavr.Lazy
+
 <!--
 - io.vavr.collection.*
 - io.vavr.concurrent.*

src/main/java/de/befrish/jqwik/vavr/VavrArbitraries.java

@@ -2,8 +2,10 @@
 
 import de.befrish.jqwik.vavr.arbitraries.VavrListArbitrary;
 import de.befrish.jqwik.vavr.arbitraries.VavrSetArbitrary;
+import de.befrish.jqwik.vavr.arbitraries.impl.DefaultVavrLazyArbitrary;
 import de.befrish.jqwik.vavr.arbitraries.impl.DefaultVavrListArbitrary;
 import de.befrish.jqwik.vavr.arbitraries.impl.DefaultVavrSetArbitrary;
+import de.befrish.jqwik.vavr.arbitraries.impl.VavrLazyArbitrary;
 import net.jqwik.api.Arbitrary;
 
 /**
@@ -15,6 +17,10 @@ private VavrArbitraries() {
         super();
     }
 
+    public static <T> VavrLazyArbitrary<T> lazy(final Arbitrary<T> innerArbitrary) {
+        return new DefaultVavrLazyArbitrary<>(innerArbitrary);
+    }
+
     public static <T> VavrListArbitrary<T> list(final Arbitrary<T> elementArbitrary) {
         return new DefaultVavrListArbitrary<>(elementArbitrary, elementArbitrary.isUnique());
     }

src/main/java/de/befrish/jqwik/vavr/arbitraries/impl/DefaultVavrLazyArbitrary.java

@@ -0,0 +1,20 @@
+package de.befrish.jqwik.vavr.arbitraries.impl;
+
+import io.vavr.Lazy;
+import net.jqwik.api.Arbitrary;
+
+/**
+ * @author Benno Müller
+ */
+public class DefaultVavrLazyArbitrary<T> extends SinglevalueArbitraryBase<T, Lazy<T>> implements VavrLazyArbitrary<T> {
+
+    public DefaultVavrLazyArbitrary(final Arbitrary<T> innerArbitrary) {
+        super(innerArbitrary);
+    }
+
+    @Override
+    protected Lazy<T> mapValue(final T value) {
+        return Lazy.of(() -> value);
+    }
+
+}

src/main/java/de/befrish/jqwik/vavr/arbitraries/impl/SinglevalueArbitraryBase.java

@@ -0,0 +1,31 @@
+package de.befrish.jqwik.vavr.arbitraries.impl;
+
+import io.vavr.Lazy;
+import net.jqwik.api.Arbitrary;
+import net.jqwik.api.EdgeCases;
+import net.jqwik.api.RandomGenerator;
+
+/**
+ * @author Benno Müller
+ */
+public abstract class SinglevalueArbitraryBase<T, U> implements Arbitrary<U> {
+
+    private final Arbitrary<T> innerArbitrary;
+
+    public SinglevalueArbitraryBase(final Arbitrary<T> innerArbitrary) {
+        this.innerArbitrary = innerArbitrary;
+    }
+
+    protected abstract U mapValue(T value);
+
+    @Override
+    public RandomGenerator<U> generator(int genSize) {
+        return innerArbitrary.generator(genSize).map(this::mapValue);
+    }
+
+    @Override
+    public EdgeCases<U> edgeCases() {
+        return innerArbitrary.edgeCases().map(this::mapValue);
+    }
+
+}

src/main/java/de/befrish/jqwik/vavr/arbitraries/impl/VavrLazyArbitrary.java

@@ -0,0 +1,10 @@
+package de.befrish.jqwik.vavr.arbitraries.impl;
+
+import io.vavr.Lazy;
+import net.jqwik.api.Arbitrary;
+
+/**
+ * @author Benno Müller
+ */
+public interface VavrLazyArbitrary<T> extends Arbitrary<Lazy<T>> {
+}

src/main/java/de/befrish/jqwik/vavr/providers/AbstractVavrCollectionArbitraryProvider.java renamed to src/main/java/de/befrish/jqwik/vavr/providers/AbstractVavrContainerArbitraryProvider.java

@@ -12,7 +12,7 @@
  *
  * @author Benno Müller
  */
-abstract class AbstractVavrCollectionArbitraryProvider implements ArbitraryProvider {
+abstract class AbstractVavrContainerArbitraryProvider implements ArbitraryProvider {
 
     @Override
     public boolean canProvideFor(final TypeUsage targetType) {
@@ -23,9 +23,9 @@ public boolean canProvideFor(final TypeUsage targetType) {
 
     @Override
     public Set<Arbitrary<?>> provideFor(final TypeUsage targetType, final SubtypeProvider subtypeProvider) {
-        final TypeUsage elementType = targetType.getTypeArgument(0);
-        final Set<Arbitrary<?>> elementArbitraries = subtypeProvider.apply(elementType);
-        return elementArbitraries.stream()
+        final TypeUsage innerType = targetType.getTypeArgument(0);
+        final Set<Arbitrary<?>> innerArbitraries = subtypeProvider.apply(innerType);
+        return innerArbitraries.stream()
                 .map(this::create)
                 .collect(Collectors.toSet());
     }

src/main/java/de/befrish/jqwik/vavr/providers/VavrLazyArbitraryProvider.java

@@ -0,0 +1,26 @@
+package de.befrish.jqwik.vavr.providers;
+
+import de.befrish.jqwik.vavr.arbitraries.impl.DefaultVavrLazyArbitrary;
+import de.befrish.jqwik.vavr.arbitraries.impl.VavrLazyArbitrary;
+import io.vavr.Lazy;
+import net.jqwik.api.Arbitrary;
+import net.jqwik.api.providers.ArbitraryProvider;
+import org.kohsuke.MetaInfServices;
+
+/**
+ * @author Benno Müller
+ */
+@MetaInfServices(ArbitraryProvider.class)
+public class VavrLazyArbitraryProvider extends AbstractVavrContainerArbitraryProvider {
+
+    @Override
+    protected Class<?> getProvidedType() {
+        return Lazy.class;
+    }
+
+    @Override
+    protected VavrLazyArbitrary<?> create(final Arbitrary<?> innerArbitrary) {
+        return new DefaultVavrLazyArbitrary<>(innerArbitrary);
+    }
+
+}

src/main/java/de/befrish/jqwik/vavr/providers/VavrListArbitraryProvider.java

@@ -11,7 +11,7 @@
  * @author Benno Müller
  */
 @MetaInfServices(ArbitraryProvider.class)
-public class VavrListArbitraryProvider extends AbstractVavrCollectionArbitraryProvider {
+public class VavrListArbitraryProvider extends AbstractVavrContainerArbitraryProvider {
 
     @Override
     protected Class<?> getProvidedType() {

src/main/java/de/befrish/jqwik/vavr/providers/VavrSetArbitraryProvider.java

@@ -12,7 +12,7 @@
  * @author Benno Müller
  */
 @MetaInfServices(ArbitraryProvider.class)
-public class VavrSetArbitraryProvider extends AbstractVavrCollectionArbitraryProvider {
+public class VavrSetArbitraryProvider extends AbstractVavrContainerArbitraryProvider {
 
     @Override
     protected Class<?> getProvidedType() {

src/test/java/de/befrish/jqwik/vavr/providers/VavrLazyArbitraryProviderTest.java

@@ -0,0 +1,53 @@
+package de.befrish.jqwik.vavr.providers;
+
+import de.befrish.jqwik.vavr.VavrArbitraries;
+import io.vavr.Lazy;
+import io.vavr.collection.List;
+import net.jqwik.api.Arbitraries;
+import net.jqwik.api.Arbitrary;
+import net.jqwik.api.ForAll;
+import net.jqwik.api.From;
+import net.jqwik.api.Property;
+import net.jqwik.api.Provide;
+import net.jqwik.api.constraints.IntRange;
+import net.jqwik.api.constraints.NotEmpty;
+import net.jqwik.api.constraints.Positive;
+import net.jqwik.api.constraints.Size;
+import net.jqwik.api.constraints.Unique;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.emptyIterable;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
+import static org.hamcrest.Matchers.not;
+
+/**
+ * @author Benno Müller
+ */
+class VavrLazyArbitraryProviderTest {
+
+    @Property
+    void generate(@ForAll final Lazy<Integer> lazy) {
+        // Test that the ArbitraryProvider works (fails if not found)
+    }
+
+    @Property
+    void generateWithValueContrains(@ForAll final Lazy<@IntRange(min = 3, max = 42) Integer> lazy) {
+        final Integer value = lazy.get();
+        assertThat(value, is(greaterThanOrEqualTo(3)));
+        assertThat(value, is(lessThanOrEqualTo(42)));
+    }
+
+    @Provide
+    Arbitrary<Lazy<Integer>> integersMin3() {
+        return VavrArbitraries.lazy(Arbitraries.integers().greaterOrEqual(3));
+    }
+
+    @Property
+    void generateFrom(@ForAll @From("integersMin3") final Lazy<Integer> lazy) {
+        assertThat(lazy.get(), is(greaterThanOrEqualTo(3)));
+    }
+
+}