E · AdvancedAdvanced45 min read
10. GraphQL testing basics
API Testing · 44 pages source format
Many teams use GraphQL. Testing differs from REST — queries, mutations, errors array, and no over-fetching assertions.
What you'll learn
- Query vs mutation
- GraphQL errors format
- Postman GraphQL
- When REST vs GraphQL tests differ
First GraphQL query
POST to /graphql with { "query": "{ users { id name } }" }. Single endpoint, typed schema.
Do this now
Use Postman GraphQL mode or curl against a public GraphQL API (e.g. SpaceX demo).
Clear?
Assert data and errors
Response: { data: {...}, errors: [...] }. Assert both paths — partial errors are common.
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Send invalid query. Assert errors array non-empty and data null or partial.
Clear?
Strategy note
Same pyramid applies — test resolvers at unit level when possible, integration at GraphQL layer.
Do this now
Add GraphQL section to STRATEGY.md (half page).
Clear?