Add TDD with AI agents tutorial

tdd-ai-agents/.claude/settings.json

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+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Edit|Write",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "jq -e '.tool_input.file_path | contains(\"/tests/\")' >/dev/null && echo 'tests/ is read-only during implementation' >&2 && exit 2 || exit 0"
+          }
+        ]
+      }
+    ]
+  }
+}

tdd-ai-agents/.gitignore

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+# Virtual environment
+venv/
+.venv/
+
+# Python cache
+__pycache__/
+*.py[cod]
+
+# Testing
+.pytest_cache/
+
+# OS files
+.DS_Store

tdd-ai-agents/README.md

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+# TDD With AI Agents: Design the Tests First, Let the Agent Implement
+This folder contains sample code for the Real Python tutorial [TDD With AI Agents: Design the Tests First, Let the Agent Implement].

tdd-ai-agents/pyproject.toml

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+[project]
+name = "version-check"
+version = "0.1.0"
+
+[build-system]
+requires = ["setuptools"]
+build-backend = "setuptools.build_meta"

tdd-ai-agents/tests/test_core.py

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+import pytest
+from version_check import Version
+
+
+def test_equal_versions_compare_equal():
+    assert Version("1.2.0") == Version("1.2.0")
+
+
+def test_smaller_release_sorts_first():
+    assert Version("1.2.0") < Version("1.3.0")
+
+
+def test_double_digit_segments_sort_numerically():
+    assert Version("3.9") < Version("3.10")
+
+
+@pytest.mark.parametrize(
+    "lower, higher",
+    [
+        ("1.0.dev1", "1.0"),  # Dev before final
+        ("1.0a1", "1.0"),  # Pre-release before final
+        ("1.0", "1.0.post1"),  # Post-release after final
+        ("1.0.dev1", "1.0a1"),  # Dev before pre-release
+        ("1.0a1", "1.0b1"),  # Alpha before beta
+        ("1.0b1", "1.0rc1"),  # Beta before release candidate
+        ("1.0.dev1", "1.0.post1"),  # Dev before post, spanning the release
+    ],
+)
+def test_phase_ordering(lower, higher):
+    assert Version(lower) < Version(higher)
+
+
+@pytest.mark.parametrize(
+    "text",
+    [
+        "",  # Empty string
+        "   ",  # Whitespace only
+        "1.x.0",  # Non-numeric segment
+        "banana",  # Not a version at all
+        "1..0",  # Empty segment
+        "v1.0",  # Leading junk
+    ],
+)
+def test_invalid_input_raises(text):
+    with pytest.raises(ValueError):
+        Version(text)

tdd-ai-agents/version_check/__init__.py

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+from version_check.core import Version
+
+__all__ = ["Version"]

tdd-ai-agents/version_check/core.py

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+import re
+from functools import total_ordering
+
+_VERSION = re.compile(
+    r"^\s*(?P<release>\d+(?:\.\d+)*)"
+    r"(?:(?P<pre_label>a|b|rc)(?P<pre_num>\d+))?"
+    r"(?:\.dev(?P<dev>\d+))?"
+    r"(?:\.post(?P<post>\d+))?\s*$"
+)
+_PRE_ORDER = {"a": 0, "b": 1, "rc": 2}
+
+
+@total_ordering
+class Version:
+    def __init__(self, text):
+        match = _VERSION.match(text)
+        if match is None:
+            raise ValueError(f"invalid version string: {text!r}")
+        self._release = tuple(
+            int(part) for part in match["release"].split(".")
+        )
+        if match["pre_label"] is not None:
+            self._pre = (_PRE_ORDER[match["pre_label"]], int(match["pre_num"]))
+        else:
+            self._pre = None
+        self._dev = int(match["dev"]) if match["dev"] else None
+        self._post = int(match["post"]) if match["post"] else None
+
+    def _key(self):
+        if self._dev is not None and self._pre is None and self._post is None:
+            phase = (0, self._dev)
+        elif self._pre is not None:
+            phase = (1, self._pre)
+        elif self._post is not None:
+            phase = (3, self._post)
+        else:
+            phase = (2, 0)
+        return (self._release, phase)
+
+    def __eq__(self, other):
+        if not isinstance(other, Version):
+            return NotImplemented
+        return self._key() == other._key()
+
+    def __lt__(self, other):
+        if not isinstance(other, Version):
+            return NotImplemented
+        return self._key() < other._key()