pytest-api-cov 0.1.3

Api Coverage Report Pytest Plugin

pytest-api-cov

A pytest plugin that measures API endpoint coverage for FastAPI and Flask applications. Know which endpoints are tested and which are missing coverage.

Features

• Zero Configuration: Plug-and-play with Flask/FastAPI apps - just install and run
• Terminal Reports: Rich terminal output with detailed coverage information
• JSON Reports: Export coverage data for CI/CD integration
• Setup Wizard: Interactive setup wizard for complex projects

Quick Start

Installation

pip install pytest-api-cov

Basic Usage

For most projects, no configuration is needed:

# Just add the flag to your pytest command
pytest --api-cov-report

The plugin will automatically discover your Flask/FastAPI app if it's in common locations:

• app.py (with variable app, application, or main)
• main.py (with variable app, application, or main)
• server.py (with variable app, application, or server)

Example

Given this FastAPI app in app.py:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello World"}

@app.get("/users/{user_id}")
def get_user(user_id: int):
    return {"user_id": user_id}

@app.get("/health")
def health_check():
    return {"status": "ok"}

And this test file:

def test_root_endpoint(client):
    response = client.get("/")
    assert response.status_code == 200

def test_get_user(client):
    response = client.get("/users/123")
    assert response.status_code == 200

Running pytest --api-cov-report produces:

API Coverage Report
Uncovered Endpoints:
  [X] /health

Total API Coverage: 66.67%

Advanced Configuration

Setup Wizard

If auto-discovery doesn't work for your project, use the interactive setup wizard:

pytest-api-cov init

This will:

• Detect your framework and app location
• Create a conftest.py fixture if needed
• Generate suggested pyproject.toml configuration

Manual Configuration

Create a conftest.py file:

import pytest
from your_app import app

@pytest.fixture
def app():
    return app

Configuration Options

Add configuration to your pyproject.toml:

[tool.pytest_api_cov]
# Fail if coverage is below this percentage
fail_under = 80.0

# Control what's shown in reports
show_uncovered_endpoints = true
show_covered_endpoints = false
show_excluded_endpoints = false

# Exclude endpoints from coverage using simple wildcard patterns
# Use * for wildcard matching, all other characters are matched literally
exclusion_patterns = [
    "/health",        # Exact match
    "/metrics",       # Exact match
    "/docs/*",        # Wildcard: matches /docs/swagger, /docs/openapi, etc.
    "/admin/*",       # Wildcard: matches all admin endpoints
    "/api/v1.0/*"     # Exact version match (won't match /api/v1x0/*)
]

# Save detailed JSON report
report_path = "api_coverage.json"

# Force Unicode symbols in output
force_sugar = true

# Force no Unicode symbols in output
force_sugar_disabled = true

Command Line Options

# Basic coverage report
pytest --api-cov-report

# Set coverage threshold to fail test session
pytest --api-cov-report --api-cov-fail-under=80

# Show covered endpoints
pytest --api-cov-report --api-cov-show-covered-endpoints

# Show excluded endpoints
pytest --api-cov-report --api-cov-show-excluded-endpoints

# Hide uncovered endpoints
pytest --api-cov-report --api-cov-show-uncovered-endpoints=false

# Save JSON report
pytest --api-cov-report --api-cov-report-path=api_coverage.json

# Exclude specific endpoints (supports wildcards)
pytest --api-cov-report --api-cov-exclusion-patterns="/health" --api-cov-exclusion-patterns="/docs/*"

# Verbose logging (shows discovery process)
pytest --api-cov-report -v

# Debug logging (very detailed)
pytest --api-cov-report -vv

Framework Support

Works automatically with FastAPI and Flask applications.

FastAPI

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()

@app.get("/items/{item_id}")
def read_item(item_id: int):
    return {"item_id": item_id}

# Tests automatically get a 'client' fixture
def test_read_item(client):
    response = client.get("/items/42")
    assert response.status_code == 200

Flask

from flask import Flask

app = Flask(__name__)

@app.route("/users/<int:user_id>")
def get_user(user_id):
    return {"user_id": user_id}

# Tests automatically get a 'client' fixture  
def test_get_user(client):
    response = client.get("/users/123")
    assert response.status_code == 200

Parallel Testing

pytest-api-cov fully supports pytest-xdist for parallel test execution:

# Run tests in parallel with coverage
pytest --api-cov-report -n auto

Coverage data is automatically collected from all worker processes and merged in the final report.

JSON Report Format

When using --api-cov-report-path, the plugin generates a detailed JSON report:

{
  "status": 0,
  "coverage": 66.67,
  "required_coverage": 80.0,
  "total_endpoints": 3,
  "covered_count": 2,
  "uncovered_count": 1,
  "excluded_count": 0,
  "detail": [
    {
      "endpoint": "/",
      "callers": ["test_root_endpoint"]
    },
    {
      "endpoint": "/users/{user_id}",
      "callers": ["test_get_user"]
    },
    {
      "endpoint": "/health",
      "callers": []
    }
  ]
}

CI/CD Integration

Fail on Low Coverage

# Fail the build if coverage is below 80%
pytest --api-cov-report --api-cov-fail-under=80

GitHub Actions Example

name: API Coverage
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v4
    - uses: actions/setup-python@v4
      with:
        python-version: '3.12'
    - run: pip install pytest pytest-api-cov
    - run: pytest --api-cov-report --api-cov-fail-under=80 --api-cov-report-path=coverage.json
    - uses: actions/upload-artifact@v4
      with:
        name: api-coverage-report
        path: coverage.json

Troubleshooting

No App Found

If you see "No API app found", ensure:

1. Your app is in a standard location (app.py, main.py, etc.)
2. Your app variable has a standard name (app, application, main)
3. Your app imports are correct (from fastapi import FastAPI or from flask import Flask)

Or use the setup wizard: pytest-api-cov init

No Endpoints Discovered

If you see "No endpoints discovered":

1. Check that your app is properly instantiated
2. Verify your routes/endpoints are defined
3. Ensure the client fixture is working in your tests
4. Use -v or -vv for debug information

Framework Not Detected

The plugin supports:

• FastAPI: Detected by from fastapi import or import fastapi
• Flask: Detected by from flask import or import flask

Other frameworks are not currently supported.

License

This project is licensed under the Apache License 2.0.