Add tests for primary/fallback/defaultCandidate precedence

Closes gh-34449

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

@@ -113,6 +113,7 @@ import static org.mockito.Mockito.verify;
  * @author Chris Beams
  * @author Phillip Webb
  * @author Stephane Nicoll
+ * @author Yanming Zhou
  */
 class DefaultListableBeanFactoryTests {
 
@@ -1665,6 +1666,60 @@ class DefaultListableBeanFactoryTests {
 		assertThat(lbf.containsSingleton("bd1")).isFalse();
 	}
 
+	@Test
+	void getBeanByTypeWithUniqueNonFallbackDefinition() {
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setLazyInit(true);
+		bd1.setFallback(true);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setFallback(true);
+		RootBeanDefinition bd3 = new RootBeanDefinition(TestBean.class);
+		lbf.registerBeanDefinition("bd1", bd1);
+		lbf.registerBeanDefinition("bd2", bd2);
+		lbf.registerBeanDefinition("bd3", bd3);
+
+		TestBean bean = lbf.getBean(TestBean.class);
+		assertThat(bean.getBeanName()).isEqualTo("bd3");
+		assertThat(lbf.containsSingleton("bd1")).isFalse();
+	}
+
+	@Test
+	void getBeanByTypeWithPrimaryAndUniqueNonFallbackDefinition() {
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setLazyInit(true);
+		bd1.setFallback(true);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setPrimary(true);
+		bd2.setFallback(true);
+		RootBeanDefinition bd3 = new RootBeanDefinition(TestBean.class);
+		lbf.registerBeanDefinition("bd1", bd1);
+		lbf.registerBeanDefinition("bd2", bd2);
+		lbf.registerBeanDefinition("bd3", bd3);
+
+		TestBean bean = lbf.getBean(TestBean.class);
+		assertThat(bean.getBeanName()).isEqualTo("bd2");
+		assertThat(lbf.containsSingleton("bd1")).isFalse();
+	}
+
+	@Test
+	void getBeanByTypeWithUniqueNonFallbackAndUniqueNonDefaultDefinition() {
+		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);
+		bd1.setLazyInit(true);
+		bd1.setFallback(true);
+		RootBeanDefinition bd2 = new RootBeanDefinition(TestBean.class);
+		bd2.setFallback(true);
+		bd2.setDefaultCandidate(false);
+		RootBeanDefinition bd3 = new RootBeanDefinition(TestBean.class);
+		bd3.setDefaultCandidate(false);
+		lbf.registerBeanDefinition("bd1", bd1);
+		lbf.registerBeanDefinition("bd2", bd2);
+		lbf.registerBeanDefinition("bd3", bd3);
+
+		TestBean bean = lbf.getBean(TestBean.class);
+		assertThat(bean.getBeanName()).isEqualTo("bd3");
+		assertThat(lbf.containsSingleton("bd1")).isFalse();
+	}
+
 	@Test
 	void getBeanByTypeWithUniqueNonDefaultDefinition() {
 		RootBeanDefinition bd1 = new RootBeanDefinition(TestBean.class);