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ITK3 Test Harness - tips for implementers

Top tips for implementers in relation to HAPI validation reports output by the ITK3 Test Harness.

ITK3 Test Harness validation

The ITK3 Test Harness tool validates message instances against NHS Digital FHIR profiles using the HAPI (HL7 application programming interface) validation tool, which is built into the Harness. This tool generates validation reports against message instances and profiles referenced therein when it is sent to the Test Harness. The reports are available for registered users to access on the ITK3 Test Harness portal and/or by return of email. Further information on obtaining credentials for accessing this portal is available in the NHS Digital ITK3 Test Harness user guidance.

HAPI validation reports – errors, warnings and information entries

Below is some guidance on what a user might expect to see in a HAPI validation report.

Validation entries in the reports fall into three categories:

Validation report errors

An error in a validation report indicates that there is an error in a message or in a referenced profile and these must be investigated by the sender and the identified issue should be fixed.

Errors are prefixed by the text:


The sender should make any fixes to the sent message instances and resend the message. If it is suspected that the cause of an error is in the referenced profile, please contact including the full text of the error, warning or informational alert and attaching the message instance that generated the issue.

Validation report warnings

A warning in a validation report could be caused by an error in a message or in a referenced profile and the cause should be investigated by the sender. Any error identified should be fixed.

Warnings are prefixed by the text:


Validation report information entries

These are for informational purposes and are unlikely to be caused by an error in the message or referenced profile. However, the cause of the informational entry should be investigated and understood by the sender and any necessary fixes made.

Informational entries are prefixed by the text:


Sample error, warning and information validation entries

Validation entries show the location and detail of the issue.

Sample error alert

The error alert below shows that the value entered in the message does not match the fixed value in the FHIR profile. Action is required from the sender to correct the message contents.

FAIL ERROR — DOCUMENT BUNDLE: Value is ‘Allergies and adverse reaction’ but must be ‘Allergies and adverse reactions’ * Location: Bundle.entry[1].resource.section[1].title column: 0

Sample warning alert

The warning alert below shows that the document bundle contains an element with a value which has either preceding or trailing whitespace.

FAIL WARNING — DOCUMENT BUNDLE: value should not start or finish with whitespace * Location: Bundle.entry[12] column: 0

Sample information alert

The informational alert below tells the message sender that a slice in the sent message does not match any known slice in the referenced profile.

FAIL INFORMATION — DOCUMENT BUNDLE: This element does not match any known slice for the profile * Location: Bundle.entry[2].resource.type.coding column: 0

Known issues

The following HAPI validation errors and informational messages are known issues and do not indicate errors in messages sent to the ITK3 Test Harness:-

  • ERROR — Problem evaluating slicing expression for element in profile path Bundle.entry[4].resource.entry[4][1] (fhirPath = true and (use memberOf ‘’))
  • ERROR — Entry isn’t reachable by traversing from first Bundle entry
  • INFORMATION — Could not verify slice for profile
Last edited: 12 July 2019 11:01 am