diff --git a/hapi-fhir-validation/src/test/java/org/hl7/fhir/dstu3/hapi/validation/FhirInstanceValidatorDstu3Test.java b/hapi-fhir-validation/src/test/java/org/hl7/fhir/dstu3/hapi/validation/FhirInstanceValidatorDstu3Test.java
index d70e954e70c..b4f5037a231 100644
--- a/hapi-fhir-validation/src/test/java/org/hl7/fhir/dstu3/hapi/validation/FhirInstanceValidatorDstu3Test.java
+++ b/hapi-fhir-validation/src/test/java/org/hl7/fhir/dstu3/hapi/validation/FhirInstanceValidatorDstu3Test.java
@@ -408,6 +408,25 @@ public class FhirInstanceValidatorDstu3Test {
 
 	}
 
+	/**
+	 * See #851
+	 */
+	@Test
+	public void testValidateCoding() {
+		ImagingStudy is = new ImagingStudy();
+		is.setUid(IdType.newRandomUuid().getValue());
+		is.getPatient().setReference("Patient/1");
+
+		is.getModalityListFirstRep().setSystem("http://foo");
+		is.getModalityListFirstRep().setCode("BAR");
+		is.getModalityListFirstRep().setDisplay("Hello");
+
+		ValidationResult results = myVal.validateWithResult(is);
+		List<SingleValidationMessage> outcome = logResultsAndReturnNonInformationalOnes(results);
+		assertThat(outcome, empty());
+
+	}
+
 	/**
 	 * FHIRPathEngine was throwing Error...
 	 */