[Draft] Update data test descriptions

website/docs/docs/build/data-tests.md

@@ -267,6 +267,14 @@ where {{ column_name }} is null
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+## Document data test descriptions
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+The details of data tests are available to view in dbt Explorer (Cloud) or by executing `dbt docs generate` and `dbt docs view` (Core). In addition to general details such as date, time run, and last run status, you can add a custom description using the `description` configuration in project .yml files. The description field can contain plain text or macro configurations and can be added to the `/test` directory in a .yml file (for example, `schema.yml`). Additionally, if you add the `description` config to the test in a model's .yml file, it will be documented as well. 
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 ## Storing test failures
 
 Normally, a data test query will calculate failures as part of its execution. If you set the optional `--store-failures` flag,  the [`store_failures`](/reference/resource-configs/store_failures), or the [`store_failures_as`](/reference/resource-configs/store_failures_as) configs, dbt will first save the results of a test query to a table in the database, and then query that table to calculate the number of failures.