Setup for Data Quality Rules engine

It’s possible to use NBi as a data quality rules engine. The assertions equal-to (subset-of, superset-of), unique-rows, row-count (all/no/single/some-rows) are supported in this context.

The gap between a data quality rule engine and an automated test framework is especially in the reporting. When using an automated testing tool, you usually don’t care of details when a test is successful. At the opposite, a data quality rules engine will need to report (at the minimum) how many rows were successful. To achieve this, NBi lets you configure a few specific attributes that you won’t use in when you’re targeting an automated testing tool.

A valid configuration, to use NBi as a data quality rules engine, is to set the format to JSON and the mode to Always (in place of respectively Markdown and OnFailure which are the default values).


These two settings will enable NBi to always add to the result file some information about the tests in a JSON format.

The JSON content is embedded in the element message of the xml file containing the results. This JSON document has the following structure: 3 items named

  • actual: a table information for the actual result-set
  • expected: a table information for the expected result-set [Only for equal-to, subset-of, superset-of]
  • analysis: some tables information for the analysis

Depending on the type of the constraint, the item analysis could contain tables unexpected-rows, missing-rows, duplicated-rows, …

Each table information contains the row-count, if sampled the row-count of the sampled result-set, the structure of the result-set (for each column, the properties such as role, type, tolerance, roundings, …) and the rows. The representation of the value of each cell is in a text format independently of the underlying type. This is a choice made to let you capture specific values such as (any), (value) or (empty).

<test-case name="NBi.NUnit.Runtime.TestSuite.Simple equalTo with Failure" description="" executed="True" result="Error" success="False" time="1.351" asserts="1">
<category name="Execution" />
<message><![CDATA[NBi.NUnit.Runtime.CustomStackTraceAssertionException : {"expected":{"total-rows":2,"table":{"columns":[{"position":0,"name":"Column1","role":"KEY","type":"Text"},{"position":1,"name":"Column2","role":"VALUE","type":"Numeric"}],"rows":[["Alpha","1"],["Beta","3"]]}},"actual":{"total-rows":2,"table":{"columns":[{"position":0,"name":"Column1","role":"KEY","type":"Text"},{"position":1,"name":"Column2","role":"VALUE","type":"Numeric"}],"rows":[["Alpha","1"],["Beta","2"]]}},"analysis":{"unexpected":{"total-rows":0},"missing":{"total-rows":0},"duplicated":{"total-rows":0},"non-matching":{"total-rows":1,"table":{"columns":[{"position":0,"name":"Column1","role":"KEY","type":"Text"},{"position":1,"name":"Column2","role":"VALUE","type":"Numeric"}],"rows":[[{"value":"Beta"},{"value":"2","expectation":"3"}]]}}}}]]></message>
<stack-trace><![CDATA[<?xml version="1.0" encoding="utf-16"?>...]]></stack-trace>