Implement failFast in NestedValidator (#339)

fixes gh-335

src/main/java/am/ik/yavi/core/NestedValidator.java

@@ -60,4 +60,21 @@ public ConstraintViolations validate(T target, Locale locale,
 	public String getPrefix() {
 		return prefix;
 	}
+
+	/**
+	 * @since 0.13.1
+	 */
+	@Override
+	public Validatable<T> failFast(boolean failFast) {
+		final Validatable<N> validatable = this.validator.failFast(failFast);
+		return new NestedValidator<>(this.nested, validatable, prefix);
+	}
+
+	/**
+	 * @since 0.13.1
+	 */
+	@Override
+	public boolean isFailFast() {
+		return this.validator.isFailFast();
+	}
 }

src/test/java/am/ik/yavi/core/Gh335Test.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2018-2023 Toshiaki Maki <makingx@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package am.ik.yavi.core;
+
+import am.ik.yavi.builder.ValidatorBuilder;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+public class Gh335Test {
+
+	public static Validator<NestedObject> nestedValidator = ValidatorBuilder
+			.<NestedObject> of() //
+			.constraintOnCondition((nested, constraintGroup) -> nested.bool(),
+					c -> c.constraint(NestedObject::field, "field", Constraint::notNull)) //
+			.failFast(true) //
+			.build();
+	public static Validator<RootObject> rootValidator = ValidatorBuilder.<RootObject> of() //
+			.nest(RootObject::nested2, "nested2", nestedValidator) //
+			.failFast(true) //
+			.build();
+
+	@Test
+	void rootValidator_Should_FailFast() {
+		// Arrange
+		RootObject object = new RootObject("aaa", new NestedObject(null, true));
+
+		// Act
+		ConstraintViolations actual = rootValidator.validate(object);
+
+		// Assert
+		assertFalse(actual.isValid());
+		assertEquals(actual.size(), 1);
+	}
+
+	@Test
+	void nestedValidator_Should_FailFast() {
+		// Arrange
+		NestedObject object = new NestedObject(null, true);
+
+		// Act
+		ConstraintViolations actual = nestedValidator.validate(object);
+
+		// Assert
+		assertFalse(actual.isValid());
+		assertEquals(actual.size(), 1);
+	}
+
+	public static class NestedObject {
+		private final String field;
+		private final Boolean bool;
+
+		public NestedObject(String field, Boolean bool) {
+			this.field = field;
+			this.bool = bool;
+		}
+
+		public String field() {
+			return field;
+		}
+
+		public Boolean bool() {
+			return bool;
+		}
+	}
+
+	public static class RootObject {
+		private final String field;
+		private final NestedObject nested2;
+
+		public RootObject(String field, NestedObject nested2) {
+			this.field = field;
+			this.nested2 = nested2;
+		}
+
+		public String field() {
+			return field;
+		}
+
+		public NestedObject nested2() {
+			return nested2;
+		}
+	}
+}