opentia 1.0.5

Test Impact Analysis for C# / .NET, Java, and Node.js — selects only tests affected by a git diff.

opentia — Test Impact Analysis

Analyses a git diff and selects only the tests whose execution path could have been affected by the change. Skips the full suite on every push.

No external dependencies — Python 3.8+ stdlib only.

Language support: C# / .NET, Java (Maven / Gradle), and Node.js (Jest / Vitest — single packages and npm workspaces).

---

Requirements

Tool	Version	Purpose
Python	3.8+	Run opentia
Git	any	Diff source

---

Installation

pip install opentia

This installs the opentia command on your PATH.

---

Quick start

# Analyse the last commit
opentia --base HEAD~1 --root <path-to-your-project>

# Analyse uncommitted (staged + unstaged) changes — no commit needed
opentia --unstaged --root <path-to-your-project>

# Analyse and immediately run the selected tests
opentia --base HEAD~1 --root <path-to-your-project> --run

--root is where your .sln / .csproj / pom.xml / build.gradle / package.json lives. It does not need to be the git root — opentia locates the actual git root automatically.

---

Usage reference

opentia [OPTIONS] [-- TEST_ARGS]

  --base REF      Git ref to diff against (e.g. HEAD~1, main, origin/main)
  --head REF      Head ref to diff from (default: HEAD)
  --root DIR      Directory containing project files (default: .)
  --strategy      project | convention | symbol | hybrid (default: hybrid)
  --output, -o    human | json | github-actions | azure-devops (default: human)
  --run           Execute the test command after analysis
  --unstaged      Analyse working-tree changes instead of a git diff
  --              Everything after this is forwarded to the test runner

Output formats

# Human-readable (default)
opentia --base HEAD~1 --root .

# JSON — pipe into scripts or CI steps
opentia --base HEAD~1 --root . --output json

# GitHub Actions
opentia --base HEAD~1 --root . --output github-actions

# Azure DevOps
opentia --base HEAD~1 --root . --output azure-devops

JSON output fields

{
  "run_all": false,               // true = targeted selection was abandoned
  "language": "dotnet",          // dotnet | java | node
  "test_filter": "FullyQualifiedName~PricingServiceTests",
  "test_project_paths": ["...SampleApp.Services.Tests.csproj"],
  "affected_test_projects": ["SampleApp.Services.Tests"],
  "affected_test_classes": ["PricingServiceTests"],
  "test_command": "dotnet test \"...\" --filter \"...\"",
  "reason": "Analysis complete",
  "strategy_notes": []            // warnings / fallback explanations
}

---

Node.js projects

opentia detects Jest and Vitest automatically. For npm workspaces, each sub-package is analysed independently and the dependency graph is resolved across workspace:* references — changing a shared package triggers tests in every package that depends on it.

The test command is always a single npx jest (or npx vitest run) invocation run from the workspace root with a --testPathPattern filter.

Mixed-language monorepos

Each opentia run uses one adapter — .NET, Java, or Node — based on what it finds under --root. Point --root at each language root separately:

opentia --base HEAD~1 --root ./backend    # Java or .NET tests
opentia --base HEAD~1 --root ./frontend   # Node.js tests

In CI, run both steps. Each one exits cleanly with "no tests to run" when its language has no changes — nothing is wasted.

---

CI integration

GitHub Actions — pull request

on:
  pull_request:
    branches: [main, staging]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Test Impact Analysis
        id: tia
        run: opentia --base ${{ github.event.pull_request.base.sha }} --root . --output github-actions

      - name: Run affected tests
        if: steps.tia.outputs.has_tests == 'true'
        run: ${{ steps.tia.outputs.test_command }}

Available outputs: test_filter, run_all, has_tests, test_project_paths, test_command.

GitHub Actions — push to branch

- name: Test Impact Analysis
  id: tia
  run: opentia --base ${{ github.event.before }} --root . --output github-actions

- name: Run affected tests
  if: steps.tia.outputs.has_tests == 'true'
  run: ${{ steps.tia.outputs.test_command }}

Azure DevOps

- script: opentia --base $(System.PullRequest.TargetBranchName) --root . --output azure-devops
  displayName: Test Impact Analysis

- script: $(testCommand)
  condition: eq(variables['hasTests'], 'true')
  displayName: Run affected tests

Available variables: testFilter, runAllTests, hasTests, testProjectPaths, testCommand.