chore(ci): configure Codecov build counts and status thresholds

.codecov.yml

@@ -0,0 +1,40 @@
+# Codecov configuration for python-zk/kazoo
+# Reference: https://docs.codecov.com/docs/codecov-yaml
+
+codecov:
+  # Wait for all 28 test matrix jobs (7 Python versions x 4 ZooKeeper versions)
+  # to upload their coverage reports before calculating the final coverage status.
+  # NOTE: If the test matrix in .github/workflows/testing.yml changes (e.g. adding
+  # or removing Python or ZooKeeper versions), this number must be updated to match
+  # the new total: len(python-version) * len(zk-version).
+  after_n_builds: 28
+
+coverage:
+  status:
+    # Project coverage measures overall repository coverage against the base branch.
+    project:
+      default:
+        # 'auto' uses the coverage percentage of the base commit as the target.
+        target: auto
+        # Allow up to a 1% decrease in overall coverage to account for minor
+        # fluctuations, refactoring, or platform-specific code.
+        threshold: 1%
+        # Mark status as informational so minor drops do not block or fail PR CI checks.
+        informational: true
+
+    # Patch coverage measures test coverage specifically on the lines modified in the PR.
+    patch:
+      default:
+        # Require 80% coverage on new/changed lines rather than strict 100%,
+        # allowing for defensive error handling, deprecation warnings, or unreachable branches.
+        target: 80%
+        # Allow up to 5% variance below the target.
+        threshold: 5%
+        # Mark status as informational so uncovered edge-case branches do not fail PR CI checks.
+        informational: true
+
+comment:
+  layout: "diff, flags, files"
+  behavior: default
+  # Only post or update the PR comment once all builds are complete.
+  require_changes: false

.github/workflows/testing.yml

@@ -48,6 +48,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        # NOTE: If you add or remove Python versions or ZooKeeper versions from this
+        # matrix, you MUST update `codecov.after_n_builds` in .codecov.yml to match
+        # len(python-version) * len(zk-version) so Codecov waits for all matrix builds
+        # before evaluating coverage status checks.
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14", "pypy-3.11-v7.3.21"]
         # Friendly note: If you change the minimum zk-version here, update it in
         # ensure-zookeeper-env.sh. Additionally, if you need to change the way that

README.md

@@ -4,6 +4,7 @@ Kazoo
 [![Kazoo Awesome Testing](https://github.com/python-zk/kazoo/actions/workflows/testing.yml/badge.svg?branch=master)](https://github.com/python-zk/kazoo/actions/workflows/testing.yml?query=branch%3Amaster)
 [![Latest Version](https://img.shields.io/pypi/v/kazoo.svg)](https://pypi.org/project/kazoo/)
 [![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json)](https://github.com/astral-sh/ruff)
+[![codecov](https://codecov.io/gh/python-zk/kazoo/branch/master/graph/badge.svg)](https://codecov.io/gh/python-zk/kazoo)
 
 `kazoo` implements a higher level API to [Apache
 ZooKeeper](http://zookeeper.apache.org/) for Python clients.