[Bug] Unit test compilation error 'var is undefined' when combining a variable with math operators

[adamribaudo-velir]

Is this a new bug in dbt-core?

• I believe this is a new bug in dbt-core
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

When running a unit test for a model that contains a Jinja math operation on a variable, a compilation error occurs

Example operation

select {{ var('foo', 10 ) * 1}} as result

Error:

Compilation Error in unit_test test_unit_test (models\staging\test.yml)
  'var' is undefined. This can happen when calling a macro that does not exist. Check for typos and/or install package dependencies with "dbt deps".

Running the unit test on a Jinja variable without the math operation works successfully. Ex: select {{ var('foo', 10 ) }} as result

Expected Behavior

Expected behavior would be to compile unit test and executing the math operation on the variable.

Steps To Reproduce

1. In any dbt project, create a model called test with the following SQL:

select {{ var('foo', 10 ) * 1}} as result

2. In that model's .yml file, create a unit test as follows (the 'input' is not used, but required):

version: 2

unit_tests:
  - name: test_unit_test
    model: test
    given:
      - input: ref('stg_ga4__events')
        format: csv
        rows: |
          event_key
          A
    expect:
      format: csv
      rows: |
        result
        10

3. Run the unit test dbt test -s test_unit_test

Relevant log output

(python312env) C:\GitHub\velir-ga4-test-project>dbt test -s test_unit_test
22:04:52  Running with dbt=1.8.2
22:04:53  Registered adapter: bigquery=1.8.1
22:04:54  Found 59 models, 28 data tests, 1 seed, 1 source, 604 macros, 11 unit tests
22:04:54  
22:04:55  Concurrency: 4 threads (target='dev')
22:04:55  
22:04:55  1 of 1 START unit_test test::test_unit_test .................................... [RUN]
22:04:55  1 of 1 ERROR test::test_unit_test .............................................. [ERROR in 0.01s]
22:04:55  
22:04:55  Finished running 1 unit test in 0 hours 0 minutes and 1.22 seconds (1.22s).
22:04:55  
22:04:55  Completed with 1 error and 0 warnings:
22:04:55
22:04:55    Compilation Error in unit_test test_unit_test (models\staging\test.yml)
  'var' is undefined. This can happen when calling a macro that does not exist. Check for typos and/or install package dependencies with "dbt deps".
22:04:55
22:04:55  Done. PASS=0 WARN=0 ERROR=1 SKIP=0 TOTAL=1

Environment

- OS: Windows
- Python: 3.12
- dbt-core: 1.8.3, bigquery: 1.8.3

Which database adapter are you using with dbt?

bigquery

Additional Context

No response

[dkultasev]

I can also add that it doesn't work even if you add this variable to overrides->vars

[dbeatty10]

Thanks for reporting this @adamribaudo-velir and @dkultasev for confirming.

I also observed the same thing. Simplified reprex below.

models/_unit_tests.yml

version: 2

unit_tests:
  - name: test_unit_test
    model: test
    given: []
    expect:
      format: csv
      rows: |
        result
        10

This worked for models/test.sql:

select {{ var('foo', 10) }} as result

But it didn't when I changed it to this:

select {{ var('foo', 10) * 1 }} as result

$ dbt build -s test

00:11:04  Running with dbt=1.8.3
00:11:04  Registered adapter: duckdb=1.8.1
00:11:05  Found 1 model, 406 macros, 1 unit test
00:11:05  
00:11:05  Concurrency: 1 threads (target='dev')
00:11:05  
00:11:05  1 of 2 START unit_test test::test_unit_test .................................... [RUN]
00:11:05  1 of 2 ERROR test::test_unit_test .............................................. [ERROR in 0.01s]
00:11:05  2 of 2 SKIP relation feature_456.test .......................................... [SKIP]
00:11:05  
00:11:05  Finished running 1 unit test, 1 view model in 0 hours 0 minutes and 0.19 seconds (0.19s).
00:11:05  
00:11:05  Completed with 1 error and 0 warnings:
00:11:05  
00:11:05    Compilation Error in unit_test test_unit_test (models/_unit_tests.yml)
  'var' is undefined. This can happen when calling a macro that does not exist. Check for typos and/or install package dependencies with "dbt deps".
00:11:05  
00:11:05  Done. PASS=0 WARN=0 ERROR=1 SKIP=1 TOTAL=2

[dbeatty10]

This error message looks similar to #10410, so I suspect they may have the same underlying root cause(s).

[Aviss]

To perhaps help narrow down the problem: We ran into the same problem with env_var

{{
    config(
        materialized='incremental',
        grants = {
            'select': env_var('DBT_ENV_CUSTOM_ENV_ROLE_PREFIX') + '_some_role'
        }
    )
}}

would run into the error while

[...]
        grants = {
            'select': env_var('DBT_ENV_CUSTOM_ENV_ROLE_PREFIX')
        }
[...]

would not.

Interestingly, replacing the plus with the Jinja string concatenation operator also avoided this problem:

[...]
        grants = {
            'select': env_var('DBT_ENV_CUSTOM_ENV_ROLE_PREFIX') ~ '_some_role'
        }
[...]

[devmessias]

I found that var('foo', 10 ) * 1} dosen't work but var('foo', 10 ) works because the template is rendered with no var object specified. So var("foo", 10) will not be rendered you will get select as result discussion at #10849