Why testing ensures data quality in dbt - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why are tests important in dbt for data quality?

In dbt, tests help ensure data quality by:

• A: Automatically fixing data errors without manual checks.
• B: Detecting unexpected data issues early in the pipeline.
• C: Replacing the need for data documentation.
• D: Increasing the speed of data loading.

A Automatically fixing data errors without manual checks.

B Detecting unexpected data issues early in the pipeline.

C Replacing the need for data documentation.

D Increasing the speed of data loading.

💡 Hint

Think about what tests do before data is used.

Tests in dbt catch data problems early so they can be fixed before analysis, ensuring data quality.

❓ Predict Output

intermediate

What is the output of this dbt test result?

Given a dbt test that checks for nulls in a column, what does the test output if 3 rows have null values?

dbt

dbt test --select test_not_null_on_customer_id

Output:
Failure in test_not_null_on_customer_id
  3 rows failed the test

A Test fails due to syntax error.

B Test passes because nulls are allowed.

C Test passes with 3 null values found.

D Test fails because 3 rows have null values.

💡 Hint

Tests fail when data does not meet the condition.

The test fails because it found 3 rows with nulls, which violates the not_null condition.

❓ data_output

advanced

Identify the number of failing rows from a uniqueness test

A dbt uniqueness test on the 'order_id' column returns this output:

Failure in test_unique_order_id
  5 rows failed the test

How many duplicate 'order_id' values exist in the data?

A 10 duplicate order_id values

B No duplicates, test passed

C 5 duplicate order_id values

D Cannot determine from output

💡 Hint

Each failing row corresponds to a duplicate value.

The test reports 5 rows failing uniqueness, meaning 5 duplicate order_id values exist.

🔧 Debug

advanced

Why does this dbt test fail with a syntax error?

Consider this dbt test YAML snippet:

tests:
  - unique
  - not_null
  - accepted_values: {column: status, values: ["active", "inactive"]}

Why does this test configuration cause a syntax error?

A Missing closing bracket ']' in accepted_values list.

B Incorrect indentation of test names.

C The 'not_null' test is not supported in dbt.

D Using double quotes inside YAML is not allowed.

💡 Hint

Check the brackets and punctuation carefully.

The accepted_values list is missing the closing bracket ']', causing a syntax error.

🚀 Application

expert

How does automated testing in dbt improve data trust?

Which of the following best explains how automated testing in dbt improves trust in data for business users?

A By providing clear, repeatable checks that catch data issues early and document data expectations.

B By automatically correcting data errors without human review.

C By replacing the need for data analysts to validate reports manually.

D By speeding up data loading times through parallel processing.

💡 Hint

Think about how tests help users feel confident about data.

Automated tests in dbt create clear, repeatable checks that catch problems early and document what data should look like, building trust.