Introduction to Testing in dbt Core

Eric Arsenault
5 min readMay 14, 2023

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What is dbt Core and Why You Should Add it to Your Data Stack

dbt Core is an open-source data engineering framework used to automate the process of transforming data from raw sources into analytics-ready models. It provides a unified interface for developing and managing data pipelines, as well as reducing the time and complexity associated with building analytics solutions. dbt Core’s unique architecture combines SQL and Jinja templating to provide highly modularized, extensible, and easily maintainable code. Testing is a critical part of the data engineering workflow, as it helps ensure that resulting models are accurate and reliable. dbt Core provides several features designed to make testing easier, including assertions and test suites.

The Basics of dbt Core Testing: Types of Tests

dbt Core provides a comprehensive suite of tests to help ensure that data models and pipelines are accurate and reliable. Tests can be divided into two main categories: structural tests and semantic tests. Structural tests check the physical structure of a model, such as whether columns are present or absent, while semantic tests check the logical structure of the model, such as whether calculation logic is implemented correctly. Assertions are a type of structural test that checks the data against expected values. These tests can be used to check properties of individual datasets, such as checking if a column has the correct data type or contains specific values.

Setting Up a Testing Environment for dbt Core

Setting up a testing environment for dbt Core is an important step in ensuring data quality and accuracy. As mentioned testing involves running two main categories of tests: structural tests, which check the physical structure of a model, and semantic tests, which check the logical structure. Test suites allow multiple assertions to be grouped together and run in sequence to facilitate more comprehensive testing. Additionally, it is beneficial to set up automated processes so that any changes or updates made in the database are tested automatically when they occur. By setting up an appropriate testing environment for dbt Core, users can ensure their data remains accurate and reliable over time.

Automated processes are especially important for ensuring the timeliness of tests. Using dbt Core, users can set up jobs that run on a recurring schedule to check for any changes or updates made in the database and perform the necessary tests. These automated tests can also be used to check incoming data, as well as to checking for any discrepancies or errors.

Best Practices for Writing Tests in dbt Core

When writing tests in dbt Core, it is important to ensure that they are comprehensive, accurate and reliable. As such, best practices include defining test scenarios in detail and ensuring that the test covers all possible functions of the database. Additionally, it is important to keep tests up-to-date and ensure that any changes are tested against the existing tests.

It is also important that test results are reported accurately and communicated using some form of alerting so that any issues or discrepancies can be identified quickly. Additionally, it is important to ensure all tests are written in a way that makes them easy to understand and debug, as this will help to simplify the process of resolving any issues. Finally, automated testing is also recommended, as it can save a lot of time and effort in the long run.

Overall, dbt Core testing is an essential part of ensuring that any changes or improvements to the project do not result in unexpected consequences for downstream users. By following best practices and using the right tools, it is possible to ensure that all necessary tests are performed and any issues are identified quickly and fixed swiftly. Doing so will help keep the data stack running smoothly and efficiently, providing stakeholders with a great experience.

Troubleshooting Common Issues With Tests

Troubleshooting common issues when running tests in dbt Core can be a difficult task, especially if you don’t have the right tools or experience. It’s important to understand the fundamentals of dbt Core and how it works so that you can effectively identify any issues. The first step is to confirm that all data sources are connected properly and that all models are populated with data. Next, check for any errors or warnings in the output logs that may indicate a problem. If needed, you can also check your run_results.json file after the run. Finally, use debugging tools such as the VS Code plugin to investigate any issues further and find solutions. Learning how to write custom tests in SQL can help you quickly identify problems and take corrective action. With the right understanding of dbt Core and the right tools, you can ensure that your data models are performing as expected.

Tips for Effective Test Suites with dbt Core

Creating effective test suites with dbt Core requires a combination of best practices and advanced features. First, determine the scope of your tests and decide which data sources and models you want to validate. Try to cover every possible test case that could result in errors or incorrect data. Once you have identified all applicable tests, create custom SQL queries for each to validate the model. If needed, try to isolate and work around edge cases.

dbt Core provides a suite of advanced features to help you create robust tests, such as data snapshots and automated testing. Data snapshots allow you to compare the results of two runs over time to check for any unexpected changes in output. Automated testing lets you run regression tests on multiple models or sources concurrently and generate reports with any discrepancies.

By using dbt Core to validate data sources and models, you can be sure that your analytics are accurate and reliable. With automated testing, you can quickly identify potential issues before they impact analytical processes and flow through to stake holders. And with data snapshots, you can track changes over time to ensure that processes remain consistent. By leveraging these features, organizations can gain confidence in their data that spreads across the entire company.

Conclusion:

Analytics engineers should consider leveraging the powerful features of dbt Core to ensure their analytics are accurate and reliable. Automated testing allows for quick identification of potential issues, while data snapshots provide a way to track changes over time. With these tools at your disposal, you can rest assured that all processes remain consistent and any discrepancies will be quickly identified. By utilizing dbt Core’s automated testing capabilities, organizations can gain greater confidence in their data-driven decision making process with fewer resources expended on manual validation tasks. This enables organizations to accurately monitor the performance of their systems in order to respond quickly and appropriately to any changes that occur. By leveraging dbt Core’s automated testing capabilities, data engineers can ensure that their analytics are accurate and reliable, allowing stake holders to make informed decisions.

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Eric Arsenault
Eric Arsenault

Written by Eric Arsenault

Tech Lead | Analytics Engineering

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