TypeError: o is not a function

## Error

```
o is not a function
```

## Stack trace

```
../app/javascript/components/editor/testComponents/TestSummary.tsx:21 in TestSummary
../app/javascript/components/editor/testComponents/TestsGroupedByStatusList.tsx:12 in Tests
details
../app/javascript/components/editor/testComponents/TestsGroup.tsx:7 in TestsGroup
div
../app/javascript/components/editor/testComponents/TestsGroupedByStatusList.tsx:50 in TestsGroupedByStatusList
../app/javascript/components/editor/testComponents/TestRunOutput.tsx:7 in TestRunOutput
../app/javascript/components/editor/testComponents/TestRunSummary.tsx:187 in TestRunSummaryContent
div
../app/javascript/components/editor/testComponents/TestRunSummary.tsx:13 in TestRunSummary
```

## Tracking Details
- **Project**: exercism-js
- **Sentry**: [TypeError: o is not a function](https://thalamus-ai.sentry.io/issues/142663339/)
- **Culprit**: TestSummary(app/javascript/components/editor/testComponents/TestSummary)
- **First seen:** Aug 25, 2026

Start at app/javascript/components/editor/testComponents/TestSummary.tsx:21, then trace how it is rendered through TestsGroupedByStatusList.tsx, TestsGroup.tsx, TestRunOutput.tsx, and TestRunSummary.tsx. Identify the value being called there and verify that the affected test summary view no longer raises the reported TypeError.

Written by the indexing model from the issue text.