Running tests with dbt test - Step-by-Step Execution

Concept Flow - Running tests with dbt test

Write tests in schema.yml

↓

Run 'dbt test' command

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dbt executes tests on data

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Tests pass?

No→Show errors and failing rows

Yes↓

All tests pass

↓

End

You write tests in your dbt project, run 'dbt test', and dbt checks your data, showing results or errors.

Execution Sample

dbt

dbt test
-- runs all tests defined in schema.yml
-- checks data quality and constraints

This command runs all tests defined in your dbt project to validate your data.

Execution Table

Step	Action	Test Type	Test Target	Result	Output
1	Start dbt test	N/A	N/A	Running	Starting tests...
2	Run unique test	unique	column: user_id	Pass	No duplicates found
3	Run not_null test	not_null	column: email	Fail	Found 3 null values
4	Run accepted_values test	accepted_values	column: status	Pass	All values valid
5	Summary	N/A	N/A	Fail	1 test failed: not_null on email
6	End	N/A	N/A	Stopped	Fix errors and rerun

💡 Test run ends because one or more tests failed, showing errors for correction.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
Tests Run	0	1	2	3	3
Tests Passed	0	1	1	2	2
Tests Failed	0	0	1	1	1
Error Messages	[]	[]	["Found 3 null values in email"]	["Found 3 null values in email"]	["Found 3 null values in email"]

Key Moments - 2 Insights

Why does dbt stop the test run after a failure?

dbt runs all tests but reports failures at the end; the process shows all results but highlights failures for you to fix, as seen in step 5 of the execution_table.

What does a 'not_null' test check?

It checks that no values in the specified column are null. In the execution_table step 3, the test failed because 3 null values were found in the email column.

Visual Quiz - 3 Questions

Look at the execution_table at step 3, what was the test result for the 'not_null' test on 'email'?

A Fail

B Skipped

C Pass

D Running

💡 Hint

Check the 'Result' column in row 3 of the execution_table.

At which step does dbt report the summary of all tests?

A Step 2

B Step 3

C Step 5

D Step 6

💡 Hint

Look for the row with 'Summary' in the 'Action' column in the execution_table.

If the 'not_null' test on 'email' passed, how would the 'Tests Failed' variable change after step 3?

A It would increase by 1

B It would remain 0

C It would remain 1

D It would decrease by 1

💡 Hint

Check the variable_tracker for 'Tests Failed' after step 3 and imagine no failures occurred.

Concept Snapshot

dbt test runs data quality checks defined in schema.yml
Common tests: unique, not_null, accepted_values
Run with 'dbt test' command
Reports pass/fail for each test
Fix failures and rerun tests

Full Transcript

Running tests with dbt test involves writing tests in your dbt project files, then executing the 'dbt test' command. This command runs all defined tests such as uniqueness, not-null constraints, and accepted values on your data. The process outputs results step-by-step, showing which tests pass or fail. If any test fails, dbt reports the errors so you can fix them. After fixing, you rerun the tests to ensure data quality. This visual trace shows the flow from starting tests, running each test, reporting results, and ending with a summary.