Test impact analysis: run only the affected tests

Test impact analysis uses your repository’s graph to pick the tests a change can affect. Your CI sends the changed files, or a commit range, and Graphify returns the tests to run. When Graphify isn’t sure, it returns the full suite, so CI never skips a test silently.

Test impact analysis is available in enabled Graphify workspaces. For the full Buildkite setup, including the pipeline script, see Buildkite test selection.

How test impact analysis works

A workspace owner or admin creates a CI token under Integrations → BuildKite (Test Impact). CI tokens start with gfy_ci_ and only work on the test impact endpoint.
Your CI calls POST https://api.graphify.com/v1/repos/{repositoryId}/test-impact with the token as a bearer token.
Graphify checks that the repository belongs to the token’s workspace and that the workspace’s subscription is active.
Graphify runs the selection against the repository’s latest published graph.
The response is returned as-is: a Buildkite pipeline ({"steps": [...]}) or JSON, which you can pipe straight into buildkite-agent pipeline upload.

repositoryId is the repository’s Graphify ID, not its GitHub name.

Send changed files or a commit range

The request takes one of two diff sources. Sending both returns 422 invalid_diff_source.

Commit range
Changed files

Send the PR’s merge base and head commit. Graphify reads the diff from GitHub itself, including deletions and renames.

Request body

{
  "baseSha": "3f2c1a9",
  "headSha": "9be41d0",
  "format": "buildkite",
  "command": "pytest"
}

Commit-range mode needs a connected GitHub repository. For any other repository it returns 422 test_impact_range_unsupported.

Send the paths yourself, for example from git diff --name-status.

Request body

{
  "changedFiles": ["app/billing/invoice.py"],
  "deletedFiles": ["app/billing/legacy.py"],
  "renames": [{ "old": "app/tax.py", "new": "app/billing/tax.py" }],
  "format": "json",
  "command": "pytest"
}

A deleted file forces a full run. A rename moves selection to the new path.

Field	Type	Default	Notes
`changedFiles`	string[]	`[]`	Up to 2,000 paths, each up to 1,024 characters. Duplicates are removed. An empty list runs the full suite.
`deletedFiles`	string[]	`[]`	Up to 2,000 paths. Not allowed with a commit range.
`renames`	`{old, new}`[]	`[]`	Up to 2,000 pairs. Not allowed with a commit range.
`baseSha`, `headSha`	string	none	Hex commit SHAs, 7 to 64 characters. Send both or neither.
`format`	string	`buildkite`	`buildkite` or `json`.
`command`	string	`pytest`	The test command for the generated steps, up to 200 characters.

Unknown fields are rejected.

Ignore non-code files

You can set ignore globs for files that never affect tests, such as docs. A repository’s setting overrides the workspace default. Graphify keeps up to 200 globs, each up to 256 characters.

Limits

Each workspace can make 60 test impact requests per minute by default. The limit applies to the whole workspace, no matter how many tokens or repositories it uses. Over the limit returns 429 rate_limited. See Rate limits. A single selection can take up to about 45 seconds, so give the request a generous timeout. The Buildkite script uses 180 seconds.

Errors

Status and code	Meaning	What to do
`401`	The CI token is missing, revoked, or not a test impact token.	Create a new token and update your CI secret.
`402` `subscription_required`	”This organization’s subscription is inactive.”	Check Billing in the console.
`404` `repository_not_found`	The repository ID isn’t in the token’s workspace.	Use the Graphify ID from the same workspace.
`422` `invalid_diff_source`	Both a file list and a commit range were sent, or only one SHA.	Send one diff source.
`422` `invalid_sha`	”baseSha/headSha must be hex commit SHAs.”	Send full or short hex SHAs.
`422` `unknown_format`	”format must be one of: buildkite, json.”	Fix `format`.
`422` `test_impact_range_unsupported`	The repository isn’t connected through GitHub.	Send `changedFiles` instead.
`429` `rate_limited`	Over 60 requests per minute for the workspace.	Run the full suite, then back off.
`503` `test_impact_range_unavailable`	Graphify couldn’t read the commit range from GitHub.	Run the full suite.
`503` `test_impact_unavailable`	”Test selection is not available right now.”	Run the full suite.

Treat any 429 or 5xx as “run everything”. The Buildkite script already does this.

Buildkite test selection

The full pipeline setup.

Check impact

How Graphify traces what a change touches.

Hosted MCP

The same graph, for your coding agent.

Rate limits

Default limits for every endpoint.

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Core concepts

Features

Workspace

Support

Test impact analysis: run only the affected tests

How test impact analysis works

Send changed files or a commit range

Ignore non-code files

Limits

Errors

Buildkite test selection

Check impact

Hosted MCP

Rate limits

​How test impact analysis works

​Send changed files or a commit range

​Ignore non-code files

​Limits

​Errors

​Related

Buildkite test selection

Check impact

Hosted MCP

Rate limits

How test impact analysis works

Send changed files or a commit range

Ignore non-code files

Limits

Errors

Related