https://docs.justcat.it/reference/tests/expectations/ Recent content in Expectations on Hugo -- gohugo.io Wed, 19 Aug 2026 10:00:00 +0200 https://docs.justcat.it/reference/tests/expectations/introduction/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/introduction/ Every test definition — wherever it is stored — has an Expectation. CAT runs the test’s query (or queries), looks at what came back, and evaluates the expectation: the test is Passed when it holds and Failed when it does not. If something goes wrong before the expectation can be evaluated — a data source that does not exist, a statement the provider refuses, a timeout — the result is Error. https://docs.justcat.it/reference/tests/expectations/overview/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/overview/ This is an overview of all implemented expectations, with a link to the detailed page of each. For what an Expectation is and why a test has one or two queries, see Introduction. Expectation Queries Passes when Set is empty 1 the query returns no row Set is not empty 1 the query returns at least one row Set row count 1 the query returns exactly the number of rows you specify Sets match 2 the two queries return the same rows Contains — written as contains, first contains second or second contains first 2 one set holds every row of the other; the other may hold more Which one to use for which question, with examples, is on Which expectation when — and My expectation does not exist explains why five are enough. https://docs.justcat.it/reference/tests/expectations/set-is-empty/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/set-is-empty/ Example # You expect the provided query does not return anything. For example, if you log errors into a table and you need an automated way to check no errors are being added: Tests: - Suite: Smoke Tests Name: Table dbo.Errors is empty Data Source: DWH Query: SELECT * FROM dbo.[Errors] Expectation: set is empty Queries # One: Data source and Query (First data source and First query work too). A Second data source or Second query on the test is an error — the test ends with Error before anything runs. https://docs.justcat.it/reference/tests/expectations/set-is-not-empty/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/set-is-not-empty/ Example # A typical smoke test: after a release or a data load, a table must hold at least one row. Tests: - Suite: Smoke Tests Name: Table Dimension.Customer is loaded Data Source: DWH Query: SELECT * FROM Dimension.Customer Expectation: set is not empty Queries # One: Data source and Query (First data source and First query work too). A Second data source or Second query on the test is an error — the test ends with Error before anything runs. https://docs.justcat.it/reference/tests/expectations/set-row-count/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/set-row-count/ Example # The table must hold data of all five departments: Tests: - Name: Data of all departments are present Suite: Data quality checks Data source: HR Query: SELECT DISTINCT department_id FROM work_records Expectation: set row count Expected row count: 5 The expected number can also go into Second query — handy when the definitions live in a database table and you do not want a column that only one expectation reads: https://docs.justcat.it/reference/tests/expectations/sets-match/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/sets-match/ Sets match compares two sets from the same data source or from two different ones — Azure Databricks against a Power BI workspace, PostgreSQL against Snowflake. It is built for large volumes on modest hardware: CAT steps through both sorted sets row by row and never loads them whole. Example # You may want to verify that all customers from your CRM system are also present in your analytical system: https://docs.justcat.it/reference/tests/expectations/contains/ Tue, 25 Jan 2022 14:40:56 +0100 https://docs.justcat.it/reference/tests/expectations/contains/ Example # In this example we check that all data from a MySQL source system are present in a staging table in SQL Server. The staging table is persistent and is expected to contain more rows than the source (those that were deleted from the source already, but are kept in staging). The goal is to check that every single row from the source is present in the staging and we are not missing any rows.