DATACMNS-186 - Improved the way id properties are detected.

The id properties are now discovered by the BasicPersistentEntity during the call to addPersistentProperty(…). Beyond that the method rejects the id property if one was already set.

spring-data-commons-core/src/test/java/org/springframework/data/mapping/model/BasicPersistentEntityUnitTests.java

@@ -9,7 +9,10 @@ import java.util.Iterator;
 import java.util.SortedSet;
 
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
 import org.mockito.Mockito;
+import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.data.annotation.TypeAlias;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentEntitySpec;
@@ -23,8 +26,12 @@ import org.springframework.test.util.ReflectionTestUtils;
  * 
  * @author Oliver Gierke
  */
+@RunWith(MockitoJUnitRunner.class)
 public class BasicPersistentEntityUnitTests<T extends PersistentProperty<T>> {
 
+	@Mock
+	T property;
+
 	@Test
 	public void assertInvariants() {
 		PersistentEntitySpec.assertInvariants(createEntity(null));
@@ -90,6 +97,40 @@ public class BasicPersistentEntityUnitTests<T extends PersistentProperty<T>> {
 		assertThat(iterator.next(), is(entity.getPersistentProperty("ssn")));
 	}
 
+	/**
+	 * @see DATACMNS-186
+	 */
+	@Test
+	public void addingAndIdPropertySetsIdPropertyInternally() {
+
+		MutablePersistentEntity<Person, T> entity = createEntity(null);
+		assertThat(entity.getIdProperty(), is(nullValue()));
+
+		when(property.isIdProperty()).thenReturn(true);
+		entity.addPersistentProperty(property);
+		assertThat(entity.getIdProperty(), is(property));
+	}
+
+	/**
+	 * @see DATACMNS-186
+	 */
+	@Test
+	public void rejectsIdPropertyIfAlreadySet() {
+
+		MutablePersistentEntity<Person, T> entity = createEntity(null);
+
+		when(property.isIdProperty()).thenReturn(true);
+
+		entity.addPersistentProperty(property);
+
+		try {
+			entity.addPersistentProperty(property);
+			fail("Expected MappingException!");
+		} catch (MappingException e) {
+			// expected
+		}
+	}
+
 	private BasicPersistentEntity<Person, T> createEntity(Comparator<T> comparator) {
 		return new BasicPersistentEntity<Person, T>(ClassTypeInformation.from(Person.class), comparator);
 	}