Add missing @Test annotations

This commit also restores assertion accidentally removed in
commit 44d832158a.

See gh-17069

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySourceTests.java

@@ -179,8 +179,11 @@ class SpringIterableConfigurationPropertySourceTests {
 				DefaultPropertyMapper.INSTANCE);
 		assertThat(adapter.stream().count()).isEqualTo(2);
 		map.setThrowException(true);
+		map.put("key3", "value3");
+		assertThat(adapter.stream().count()).isEqualTo(3);
 	}
 
+	@Test
 	public void originTrackedMapPropertySourceKeyAdditionInvalidatesCache() {
 		// gh-13344
 		Map<String, Object> map = new LinkedHashMap<>();
@@ -194,6 +197,7 @@ class SpringIterableConfigurationPropertySourceTests {
 		assertThat(adapter.stream().count()).isEqualTo(3);
 	}
 
+	@Test
 	public void readOnlyOriginTrackedMapPropertySourceKeyAdditionDoesNotInvalidateCache() {
 		// gh-16717
 		Map<String, Object> map = new LinkedHashMap<>();