Improving test coverage of determinePrimaryCandidate

Added tests checking the behaviour of autowiring by type when the @Primary
annotation is present on the class. Fixed also some inconsistencies in the
code.

spring-beans/src/test/java/org/springframework/beans/factory/DefaultListableBeanFactoryTests.java

@@ -1511,6 +1511,41 @@ public class DefaultListableBeanFactoryTests {
 		assertNull(bean.getSpouse());
 	}
 
+	@Test
+	public void testAutowireBeanByTypeWithTwoMatchesAndOnePrimary() {
+		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
+		RootBeanDefinition bd = new RootBeanDefinition(TestBean.class);
+		bd.setPrimary(true);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		lbf.registerBeanDefinition("test", bd);
+		lbf.registerBeanDefinition("spouse", bd2);
+
+		DependenciesBean bean = (DependenciesBean)
+				lbf.autowire(DependenciesBean.class, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true);
+		assertThat(bean.getSpouse(), equalTo(lbf.getBean("test")));
+	}
+
+	@Test
+	public void testAutowireBeanByTypeWithTwoPrimaryCandidates() {
+		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();
+		RootBeanDefinition bd = new RootBeanDefinition(TestBean.class);
+		bd.setPrimary(true);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setPrimary(true);
+		lbf.registerBeanDefinition("test", bd);
+		lbf.registerBeanDefinition("spouse", bd2);
+
+		try {
+			lbf.autowire(DependenciesBean.class, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true);
+			fail("Should have thrown UnsatisfiedDependencyException");
+		}
+		catch (UnsatisfiedDependencyException ex) {
+			// expected
+			assertNotNull("Exception should have cause", ex.getCause());
+			assertEquals("Wrong cause type", NoUniqueBeanDefinitionException.class, ex.getCause().getClass());
+		}
+	}
+
 	@Test
 	public void testAutowireExistingBeanByName() {
 		DefaultListableBeanFactory lbf = new DefaultListableBeanFactory();