FHIR Resource Validation

FHIR Resource validation is performed by the FHIR Validator Wrapper service. When creating a Test Kit based on the Inferno Template:

• Place the .tgz IG packages for any profiles you need to validate against in lib/YOUR_TEST_KIT_NAME/igs.
• Make sure that the volume path in docker-compose.background.yml points to the above directory.

Every time an IG is added or changed, restart the validator service.

Defining Validators

The Inferno Template defines a validator in the suite, and it is not necessary to alter it unless you need multiple validators or want to add extra validator behaviors. Validators are defined with validator:

validator :optional_validator_name do
  # Read the validator URL from an environment variable
  url ENV.fetch('VALIDATOR_URL')
end

validator in the API docs

Validating FHIR Resources

The resource_is_valid? method will validate a FHIR resource and add any validation messages to the runnable.

test do
  fhir_read(:patient, '123')
  
  # Validate the resource from the last request
  if resource_is_valid?
  end
  
  # Validate some other resource
  if resource_is_valid?(resource: some_other_resource)
  end
  
  # Validate against a particular profile
  if resource_is_valid?(profile_url: 'http://example.com/fhir_profile_url')
  end
  
  # Validate using a particular named validator
  if resource_is_valid?(validator: :my_customized_validator)
  end
end

resource_is_valid? in the API docs

assert_valid_resource will validate the resource, add any validation messages to the runnable, and fail the test if the resource is invalid.

test do
  fhir_read(:patient, '123')
  
  # Use the resource from the last request
  assert_valid_resource
  
  # Validate some other resource
  assert_valid_resource(resource: some_other_resource)
  
  # Validate against a particular profile
  assert_valid_resource(profile_url: 'http://example.com/fhir_profile_url')
  
  # Validate using a particular named validator
  assert_valid_resource(validator: :my_customized_validator)
end

assert_valid_resource in the API docs

Filtering Validation Messages

If you need to ignore certain validation messages in your test kit, this can be done using the exclude_message method in the validator definition.

validator do
  url ENV.fetch('VALIDATOR_URL')
  # Messages will be excluded if the block evaluates to a truthy value
  exclude_message do |message|
    message.type == 'info' ||
      message.message.include?('message to ignore') ||
      message.message.match?(/regex_filter/)
  end
end

Performing Additional Validation

If you want to perform validation steps in addition to the FHIR validation, you can use the perform_additional_validation method in the validator definition. The method can also be used multiple times in a single validator definition to add multiple validation steps. To add additional validation messages, the block in this method must return a single Hash with a type and message, or an Array of Hashes with those keys. If the block returns nil, no new messages are added. The resource is considered invalid if any messages with a type of error are present.

validator do
  url ENV.fetch('VALIDATOR_URL')
  perform_additional_validation do |resource, profile_url|
    if something_is_wrong
      { type: 'error', message: 'something is wrong'}
    end
  end
end