Better Cloud Tests 🧵 | Dagger | Page 1

rough glen Apr 2, 2026, 5:17 PM

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Goal: tests are easily visible in cloud UI without expanding a million things, similar to Checks UI simplification

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@dawn ether there are standard semconv attributes we can use now: https://opentelemetry.io/docs/specs/semconv/registry/attributes/test/

I'm adding support for it in testctx now

OpenTelemetry

Test

Test Attributes This group describes attributes specific to software tests.
Attributes:
Key Stability Value Type Description Example Values test.case.name string The fully qualified human readable name of the test case. org.example.TestCase1.test1; example/tests/TestCase1.test1; ExampleTestCase1_test1 test.case.result.status string The status of...

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the attributes are kind of dumb tbh. i don't know why suite has such expressive ending states, but case is just pass/fail. I decided to just use suite for that, but still set case name. shrug

rough glen Apr 2, 2026, 8:31 PM

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nailed it

modern canyon Apr 2, 2026, 11:01 PM

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How does Dagger determine if something is a test? I would still rate the addition of a +test that produced some really basic junit output (function name, pass/fail, execution duration)

rough glen Apr 2, 2026, 11:22 PM

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modern canyon How does Dagger determine if something is a test? I would still rate the additio...

The UI recognizes the test.case.name span attribute referenced above, and uses presence of those spans as a strong hint for the UI to show a simplified list of the tests, instead of a raw trace. We'll support JUnit too, probably by just re-emitting it as OTel spans. Beyond trivial UI stuff, @warm seal is also cooking up some plans for how tests are represented in the DAG, to support test splitting / reruns / etc. in a nice consistent way

warm seal Apr 2, 2026, 11:27 PM

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@rough glen are those standard spans that test tooling may already be emitting? Or our own invention?

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(the otel stack is so sprawling, I wouldn't be surprised if a committee somewhere already formalized attributes)

rough glen Apr 2, 2026, 11:27 PM

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standard 🎉 - they must have added them recently ish, they didn't exist when testctx was created

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see #1489312918653894747 message

warm seal Apr 2, 2026, 11:27 PM

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They're vibe-standardizing

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Nice nice

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That opens the possibility of open compat bridges between junit and otel then?

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In either direction

rough glen Apr 2, 2026, 11:28 PM

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rough glen Apr 2, 2026, 11:29 PM

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warm seal That opens the possibility of open compat bridges between junit and otel then?

yeah true

rough glen Apr 4, 2026, 7:14 PM

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quick PR to get our test suites emitting better data: https://github.com/dagger/dagger/pull/12908

GitHub

test: bump testctx for better attributes + errors by vito · Pull R...

use standard semconv attributes for test name etc
put useful error messages on failed test spans
remove outdated, unused attributes
rename weirdly named bench prewarm attribute

Net UI effect for n...

rough glen Apr 4, 2026, 11:02 PM

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cloud UI PR, still iterating: https://github.com/dagger/dagger.io/pull/4892
preview: https://better-tests-v3.preview.dagger.cloud/dagger/checks/github.com/dagger/dagger@df7b8d614062895b03bf3422db1a4834d458a1fa?check=test-split%3Atest-modules&test=TestModule%2FTestConstructor%2Fbasic%2Ftypescript&viewMode=tests

warm seal Apr 4, 2026, 11:46 PM

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Amazing 🙂

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If you're starting to think about grouping tests over time (for analytics, flake detection etc), I have useful architectural scaffolding for you , the design docs are far along enough to be worth reading.

artifacts.md + collections.md

Between those two, you get stable coordinate system to locate the span-emitting object, across time, workspaces, and even across schema-path changes

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I'm most curious how the idea of a coordinate system informs web UI. Examples of things that have coordinates: SQL rows... spreadsheet rows... We're in familiar territory for web dev; tables, lists, filters, etc.

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Also: I think a TUI equivalent of "test view" would be amazing for local dev loop 🙂

rough glen Apr 7, 2026, 10:23 PM

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https://asciinema.org/a/904712

Found a zero-config way to do go test => OTel 🎉

Went through a few iterations, best option came down to a drop-in go test replacement, otelgotest. Tries to be even more transparent than gotestsum which takes a similar approach but has its own set of flags and needs -- to disambiguate. otelgotest on the other hand is as close to a pass-through as possible.

More details: https://github.com/dagger/otel-go/pull/2

asciinema

vito

otelgotest

Recorded by vito

GitHub

add `go test` and JUnit OpenTelemetry emitting by vito · Pull Requ...

Adds two CLIs:

./cmd/otelgotest: a drop-in go test replacement that emits test data to OpenTelemetry

usage: otelgotest ./... (same flags as go test, just passes through)

./cmd/oteljunit: loads ...

warm seal Apr 7, 2026, 10:28 PM

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rough glen https://asciinema.org/a/904712 Found a zero-config way to do `go test` => OTel ...

Wow that's huge!

rough glen Apr 7, 2026, 11:04 PM

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Here's how those two runs look in the test UI:

Still lots of room to improve, gonna try to get something shipped before I fly out Friday

warm seal Apr 7, 2026, 11:13 PM

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@rough glen side bar looks awesome, but right part is stuck on loading

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(first link)

rough glen Apr 7, 2026, 11:14 PM

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ah weird, same for me. as a workaround you can toggle between the Trace and Tests UI

warm seal Apr 7, 2026, 11:14 PM

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Every time I toggle it prompts me with the org chooser

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Note the "dagger / viewing"

rough glen Apr 7, 2026, 11:17 PM

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tried to repro the org switcher issue by swapping to my org and clicking the link, but couldn't. (it does say 'viewing' but switches OK)

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there's some known jank with the url handling already so hopefully whatever demon is lurking there gets exorcised along the way

rough glen Apr 27, 2026, 1:58 PM

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@normal basin @swift eagle could use a ✅ on https://github.com/dagger/otel-go/pull/2 - I rebased it on top of the otel bump, and it's all additive so shouldn't break anything. My plan is to eventually integrate this with dagger/go around here so Go tests automatically get emitted as OTel.

#Better Cloud Tests 🧵