3986: Remove validation of max parameter lastn and add tests (#5737)

* 3986: Remove validation of max parameter lastn and add tests

* 3986: Add bug fix to changelog

* 3986: Re-add removed import

* Prepare for merge

* Spotless

---------

Co-authored-by: James Agnew <jamesagnew@gmail.com>

hapi-fhir-docs/src/main/resources/ca/uhn/hapi/fhir/changelog/7_4_0/3986-fix-lastn-max-parameter.yaml

@@ -0,0 +1,4 @@
+---
+type: fix
+issue: 3986
+title: "Removed the validation error of the `max` query parameter on the $lastn operation. Now, the $lastn operation can be invoked with the `max` query parameter. Contribution by Gijs Groenewegen (@thetrueoneshots)."

hapi-fhir-jpaserver-base/src/main/java/ca/uhn/fhir/jpa/provider/BaseJpaResourceProviderObservation.java

@@ -84,6 +84,13 @@ public abstract class BaseJpaResourceProviderObservation<T extends IBaseResource
 			}
 			if (theMax != null) {
 				paramMap.setLastNMax(theMax.getValue());
+
+				/**
+				 * The removal of the original raw parameter is required as every implementing class
+				 * has the "Observation" resource class defined. For this resource, the max parameter
+				 * is not supported and thus has to be removed before the use of "translateRawParameters".
+				 */
+				theAdditionalRawParams.remove("max");
 			}
 			if (theCount != null) {
 				paramMap.setCount(theCount.getValue());

hapi-fhir-jpaserver-test-dstu3/src/test/java/ca/uhn/fhir/jpa/provider/dstu3/ObservationLastnDstu3Test.java

@@ -0,0 +1,37 @@
+package ca.uhn.fhir.jpa.provider.dstu3;
+
+import com.google.common.base.Charsets;
+import java.io.IOException;
+import org.apache.commons.io.IOUtils;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.not;
+
+public class ObservationLastnDstu3Test extends BaseResourceProviderDstu3Test {
+
+	/**
+	 * See #3986. Verifies that supplying the max parameter in the $lastn does not cause a validation error.
+	 */
+	@Test
+	public void testSupplyingMaxToTheLastNOPerationDoesNotCauseAValidationError() throws Exception {
+		String outcome = executeApiCall(myServerBase + "/Observation/$lastn?max=1");
+		assertThat(outcome, not(containsString("HAPI-524")));
+	}
+
+	private String executeApiCall(String theUrl) throws IOException {
+		String outcome;
+		HttpGet get = new HttpGet(theUrl);
+		CloseableHttpResponse resp = ourHttpClient.execute(get);
+		try {
+			outcome = IOUtils.toString(resp.getEntity().getContent(), Charsets.UTF_8);
+		} finally {
+			IOUtils.closeQuietly(resp);
+		}
+
+		return outcome;
+	}
+}

pom.xml

@@ -909,6 +909,10 @@
 			<id>jbonzohln</id>
 			<name>Jesse Bonzo</name>
 		</developer>
+		<developer>
+			<id>thetrueoneshots</id>
+			<name>Gijs Groenewegen</name>
+		</developer>
 	</developers>
 
 	<licenses>