DATAJPA-300 - Specifications are now more lenient against null values.

Static factory methods on Specifications are now more lenient regarding null values eventually evaluating to null predicates on concatenation attempts.

src/test/java/org/springframework/data/jpa/domain/SpecificationsUnitTests.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * 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 org.springframework.data.jpa.domain;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+import static org.springframework.data.jpa.domain.Specifications.*;
+
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+
+/**
+ * @author Oliver Gierke
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class SpecificationsUnitTests {
+
+	@Mock
+	Specification<Object> mockSpec;
+	@Mock
+	Root<Object> root;
+	@Mock
+	CriteriaQuery<?> query;
+	@Mock
+	CriteriaBuilder builder;
+
+	@Mock
+	Predicate predicate;
+
+	@Before
+	public void setUp() {
+		when(mockSpec.toPredicate(root, query, builder)).thenReturn(predicate);
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void createsSpecificationsFromNull() {
+
+		Specifications<Object> specification = where(null);
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(nullValue()));
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void negatesNullSpecToNull() {
+
+		Specifications<Object> specification = not((Specification<Object>) null);
+
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(nullValue()));
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void andConcatenatesSpecToNullSpec() {
+
+		Specifications<Object> specification = where(null);
+		specification = specification.and(mockSpec);
+
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(predicate));
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void andConcatenatesNullSpecToSpec() {
+
+		Specifications<Object> specification = where(mockSpec);
+		specification = specification.and(null);
+
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(predicate));
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void orConcatenatesSpecToNullSpec() {
+
+		Specifications<Object> specification = where(null);
+		specification = specification.or(mockSpec);
+
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(predicate));
+	}
+
+	/**
+	 * @see DATAJPA-300
+	 */
+	@Test
+	public void orConcatenatesNullSpecToSpec() {
+
+		Specifications<Object> specification = where(mockSpec);
+		specification = specification.or(null);
+
+		assertThat(specification, is(notNullValue()));
+		assertThat(specification.toPredicate(root, query, builder), is(predicate));
+	}
+}