Added test

hapi-fhir-structures-r4/src/test/java/ca/uhn/fhir/util/PropertyModifyingHelperTest.java

@@ -0,0 +1,30 @@
+package ca.uhn.fhir.util;
+
+import ca.uhn.fhir.context.FhirContext;
+import org.hl7.fhir.r4.model.Address;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class PropertyModifyingHelperTest {
+
+	private static FhirContext ourContext = FhirContext.forR4();
+
+	@Test
+	public void test() {
+		Address address = new Address();
+
+		PropertyModifyingHelper helper = new PropertyModifyingHelper(ourContext, address);
+		helper.set("line", "line1");
+		helper.set("line", "line2");
+		helper.set("city", "city");
+
+		address = (Address) helper.getBase();
+
+		assertEquals(2, address.getLine().size());
+		assertEquals("city", address.getCity());
+		assertNull(address.getCountry());
+	}
+
+}