Unit Test Assertion for Counter Fails

[nzxwang]

Hi,

I'm trying to write a unit test for an aggregate that aggregates counter metrics. My assertions are as follows:

    [[tests.outputs.conditions]]
    type = "vrl"
    source = '''
    assert_eq!(.tags.service, "product_1.component_1")
    assert_eq!(.tags.location, "environment_1.datacenter_1.shard_1")
    assert_eq!(.counter.value, 2)
    '''

The first 2 assertions on the tag work correctly, but the third assertion fails with a blatantly contradicting error message (the output payload explicitly shows the value of .counter.value being equal to 2.0:

Running tests
test logs_usage_audit ... failed

failures:

test logs_usage_audit:

check[0] for transforms ["minutely_logs_usage_audit"] failed conditions:

  condition[0]: source execution failed: 
error[E000]: function call error for "assert_eq" at (128:151): assertion failed: null == 2
  ┌─ :3:5
  │
3 │     assert_eq!(.counter.value, 2)
  │     ^^^^^^^^^^^^^^^^^^^^^^^ assertion failed: null == 2
  │
  = see language documentation at https://vrl.dev
  = try your code in the VRL REPL, learn more at https://vrl.dev/examples


output payloads from ["minutely_logs_usage_audit"] (events encoded as JSON):
  {"name":"logs_usage_audit","tags":{"location":"environment_1.datacenter_1.shard_1","service":"product_1.component_1"},"timestamp":"2024-01-11T18:14:47.209476506Z","kind":"incremental","counter":{"value":2.0}}

This also fails and claims a value of null when I try assert_eq!(.counter, 2). It seems like what I'm doing is very similar to

vector/tests/behavior/transforms/task_transform.toml

Line 90 in 2448a72

assert_eq!(.counter, 2, "incorrect counter")

. Any insights appreciated!

[jszwedko]

I think you are hitting this issue: #5521

[nzxwang]

Thanks for the quick reply! I read through the issue and I'm having trouble understanding how remap is related to the assertion function in vrl (maybe its the same)? You did confirm it here though: #5521 (comment)

In any case, do you have a recommendation for a workaround or next best way to unit test an aggregation?

[nzxwang]

And if so, why does this work?

vector/tests/behavior/transforms/task_transform.toml

Line 90 in 2448a72

assert_eq!(.counter, 2, "incorrect counter")

[jszwedko]

Ah, interesting. Did you try that in your test? .counter instead of .counter.value?

[nzxwang]

Yes I did. That fails with the same error message claiming that the value is null.