v0.0.3 — Introduces an OpenAPI-first HTTP client, updates documentation and templates to use operationId-based calls, and adds httpx as a client-side dependency.

used for server-side route binding, and refactor documentation and
templates to treat the client as a first-class contract consumer.

Key changes:
- Add OpenAPI-first client module based on httpx
- Document client usage alongside server-side binder usage
- Update mkdocs navigation to include client documentation
- Refactor CRUD and model app templates to call APIs via operationId
  instead of hardcoded paths
- Align package documentation and public API surface with client support
- Clarify server/client dependency split (fastapi vs httpx)

This establishes strict symmetry between OpenAPI-driven server binding
and OpenAPI-driven client invocation, reinforcing OpenAPI as the single
source of truth on both sides of the contract.

docs/openapi_first/client.md

@@ -0,0 +1,3 @@
+# Client
+
+::: openapi_first.client

mkdocs.yml

@@ -42,6 +42,7 @@ nav:
       - OpenAPI-First App: openapi_first/app.md
       - Route Binder: openapi_first/binder.md
       - Spec Loaders: openapi_first/loader.md
+      - Client: openapi_first/client.md
 
   - CLI:
       - Home: openapi_first/cli.md

openapi_first/__init__.py

@@ -17,11 +17,12 @@ convenience facades.
 Architecture Overview
 ----------------------------------------------------------------------
 
-The library is structured around three core responsibilities:
+The library is structured around four core responsibilities:
 
 - loader: load and validate OpenAPI 3.x specifications (JSON/YAML)
 - binder: bind OpenAPI operations to FastAPI routes via operationId
 - app: OpenAPI-first FastAPI application bootstrap
+- client: OpenAPI-first HTTP client driven by the same specification
 - errors: explicit error hierarchy for contract violations
 
 The package root acts as a **namespace**, not a facade. Consumers are
@@ -40,7 +41,8 @@ Or with Poetry:
     poetry add openapi-first
 
 Runtime dependencies are intentionally minimal:
-- fastapi
+- fastapi (server-side)
+- httpx (client-side)
 - openapi-spec-validator
 - pyyaml (optional, for YAML specs)
 
@@ -48,7 +50,7 @@ The ASGI server (e.g., uvicorn) is an application-level dependency and is
 not bundled with this library.
 
 ----------------------------------------------------------------------
-Basic Usage
+Server-Side Usage (OpenAPI → FastAPI)
 ----------------------------------------------------------------------
 
 Minimal OpenAPI-first FastAPI application:
@@ -57,7 +59,7 @@ Minimal OpenAPI-first FastAPI application:
     import my_service.routes as routes
 
     api = app.OpenAPIFirstApp(
-        openapi_path="openapi.json",
+        openapi_path="openapi.yaml",
         routes_module=routes,
         title="My Service",
         version="1.0.0",
@@ -81,6 +83,56 @@ OpenAPI snippet:
             "200":
               description: OK
 
+The binder guarantees:
+- Every OpenAPI operationId has exactly one handler
+- No undocumented routes exist
+- All mismatches fail at application startup
+
+----------------------------------------------------------------------
+Client-Side Usage (OpenAPI → HTTP Client)
+----------------------------------------------------------------------
+
+The same OpenAPI specification can be used to construct a strict,
+operationId-driven HTTP client.
+
+Client construction:
+
+    from openapi_first.loader import load_openapi
+    from openapi_first.client import OpenAPIClient
+
+    spec = load_openapi("openapi.yaml")
+
+    client = OpenAPIClient(spec)
+
+Calling operations (operationId is the API):
+
+    response = client.get_health()
+    assert response.status_code == 200
+    assert response.json() == {"status": "ok"}
+
+Path parameters must match the OpenAPI specification exactly:
+
+    response = client.get_item(
+        path_params={"item_id": 1}
+    )
+
+Request bodies are passed explicitly:
+
+    response = client.create_item(
+        body={"name": "Orange", "price": 0.8}
+    )
+
+Client guarantees:
+- One callable per OpenAPI operationId
+- No hardcoded URLs or HTTP methods in user code
+- Path and body parameters must match the spec exactly
+- Invalid or incomplete OpenAPI specs fail at client construction time
+- No schema inference or mutation is performed
+
+The client is transport-level only and returns `httpx.Response`
+objects directly. Response interpretation and validation are left to
+the consumer or higher-level layers.
+
 ----------------------------------------------------------------------
 Extensibility Model
 ----------------------------------------------------------------------
@@ -107,6 +159,7 @@ The supported public API consists of the following top-level modules:
 - openapi_first.app
 - openapi_first.binder
 - openapi_first.loader
+- openapi_first.client
 - openapi_first.errors
 
 Classes and functions should be imported explicitly from these modules.
@@ -118,8 +171,8 @@ Design Guarantees
 
 - OpenAPI is the single source of truth
 - No undocumented routes can exist
-- No OpenAPI operation can exist without a handler
-- All contract violations fail at application startup
+- No OpenAPI operation can exist without a handler or client callable
+- All contract violations fail at application startup or client creation
 - No hidden FastAPI magic or implicit behavior
 - Deterministic, testable application assembly
 - CI-friendly failure modes
@@ -131,11 +184,13 @@ enforcement over convenience shortcuts.
 from . import app
 from . import binder
 from . import loader
+from . import client
 from . import errors
 
 __all__ = [
     "app",
     "binder",
     "loader",
+    "client",
     "errors",
 ]

openapi_first/client.py

@@ -0,0 +1,176 @@
+from typing import Any, Callable, Dict, Optional
+from urllib.parse import urljoin
+
+import httpx
+
+from .errors import OpenAPIFirstError
+
+
+class OpenAPIClientError(OpenAPIFirstError):
+    """Raised when an OpenAPI client operation fails."""
+
+
+class OpenAPIClient:
+    """
+    OpenAPI-first HTTP client (httpx-based).
+
+    - One callable per operationId
+    - Explicit parameters (path, query, headers, body)
+    - No implicit schema inference or mutation
+    """
+
+    def __init__(
+        self,
+        spec: dict[str, Any],
+        base_url: Optional[str] = None,
+        client: Optional[httpx.Client] = None,
+    ) -> None:
+        self.spec = spec
+        self.base_url = base_url or self._resolve_base_url(spec)
+        self.client = client or httpx.Client(base_url=self.base_url)
+
+        self._operations: Dict[str, Callable[..., httpx.Response]] = {}
+        self._build_operations()
+
+    # ------------------------------------------------------------------ #
+    # Public API
+    # ------------------------------------------------------------------ #
+
+    def __getattr__(self, name: str) -> Callable[..., httpx.Response]:
+        try:
+            return self._operations[name]
+        except KeyError:
+            raise AttributeError(f"No such operationId: {name}") from None
+
+    def operations(self) -> Dict[str, Callable[..., httpx.Response]]:
+        return dict(self._operations)
+
+    # ------------------------------------------------------------------ #
+    # Internal mechanics
+    # ------------------------------------------------------------------ #
+
+    def _resolve_base_url(self, spec: dict[str, Any]) -> str:
+        servers = spec.get("servers")
+        if not servers:
+            raise OpenAPIClientError("No servers defined in OpenAPI spec")
+
+        url = servers[0].get("url")
+        if not url:
+            raise OpenAPIClientError("Server entry missing 'url'")
+
+        return url.rstrip("/") + "/"
+
+    def _build_operations(self) -> None:
+        paths = self.spec.get("paths", {})
+        if not paths:
+            raise OpenAPIClientError("OpenAPI spec contains no paths")
+
+        for path, path_item in paths.items():
+            for method, operation in path_item.items():
+                if method.lower() not in {
+                    "get", "post", "put", "patch", "delete", "head", "options"
+                }:
+                    continue
+
+                operation_id = operation.get("operationId")
+                if not operation_id:
+                    raise OpenAPIClientError(
+                        f"Missing operationId for {method.upper()} {path}"
+                    )
+
+                if operation_id in self._operations:
+                    raise OpenAPIClientError(
+                        f"Duplicate operationId detected: {operation_id}"
+                    )
+
+                self._operations[operation_id] = self._make_operation(
+                    method=method.upper(),
+                    path=path,
+                    operation=operation,
+                )
+
+    def _make_operation(
+        self,
+        *,
+        method: str,
+        path: str,
+        operation: dict[str, Any],
+    ) -> Callable[..., httpx.Response]:
+        request_body = operation.get("requestBody")
+
+        def call(
+            *,
+            path_params: Optional[dict[str, Any]] = None,
+            query: Optional[dict[str, Any]] = None,
+            headers: Optional[dict[str, str]] = None,
+            body: Optional[Any] = None,
+            timeout: Optional[float] = None,
+        ) -> httpx.Response:
+            url = self._build_url(path, path_params or {})
+
+            req_headers = headers.copy() if headers else {}
+
+            json_data = None
+            content = None
+
+            if request_body is not None:
+                if body is None:
+                    raise OpenAPIClientError(
+                        f"Request body required for operation {operation['operationId']}"
+                    )
+
+                media_types = request_body.get("content", {})
+                if "application/json" in media_types:
+                    json_data = body
+                    req_headers.setdefault("Content-Type", "application/json")
+                else:
+                    content = body
+
+            response = self.client.request(
+                method=method,
+                url=url,
+                params=query,
+                headers=req_headers,
+                json=json_data,
+                content=content,
+                timeout=timeout,
+            )
+
+            return response
+
+        call.__name__ = operation["operationId"]
+        call.__doc__ = self._build_docstring(method, path, operation)
+
+        return call
+
+    def _build_url(self, path: str, path_params: dict[str, Any]) -> str:
+        try:
+            formatted_path = path.format(**path_params)
+        except KeyError as exc:
+            raise OpenAPIClientError(
+                f"Missing path parameter: {exc.args[0]}"
+            ) from exc
+
+        return urljoin(self.base_url, formatted_path.lstrip("/"))
+
+    def _build_docstring(
+        self,
+        method: str,
+        path: str,
+        operation: dict[str, Any],
+    ) -> str:
+        lines = [
+            f"{method} {path}",
+            "",
+            operation.get("summary", ""),
+            "",
+            "Parameters:",
+            "  path_params: dict | None",
+            "  query: dict | None",
+            "  headers: dict | None",
+            "  body: Any | None",
+            "",
+            "Returns:",
+            "  httpx.Response",
+        ]
+        return "\n".join(lines)

openapi_first/loader.py

@@ -25,8 +25,6 @@ This module intentionally does NOT:
 - Perform request/response validation at runtime
 """
 
-from __future__ import annotations
-
 import json
 from pathlib import Path
 from typing import Any

openapi_first/templates/crud_app/data.py

@@ -0,0 +1,41 @@
+"""
+In-memory mock data store for CRUD example.
+
+This module intentionally avoids persistence and concurrency guarantees.
+It is suitable for demos, tests, and scaffolding only.
+"""
+
+from typing import Dict
+
+_items: Dict[int, dict] = {
+    1: {"id": 1, "name": "Apple", "price": 0.5},
+    2: {"id": 2, "name": "Banana", "price": 0.3},
+}
+
+_next_id = 3
+
+
+def list_items():
+    return list(_items.values())
+
+
+def get_item(item_id: int):
+    return _items[item_id]
+
+
+def create_item(payload: dict):
+    global _next_id
+    item = {"id": _next_id, **payload}
+    _items[_next_id] = item
+    _next_id += 1
+    return item
+
+
+def update_item(item_id: int, payload: dict):
+    item = {"id": item_id, **payload}
+    _items[item_id] = item
+    return item
+
+
+def delete_item(item_id: int):
+    del _items[item_id]

openapi_first/templates/crud_app/main.py

@@ -0,0 +1,8 @@
+from openapi_first.app import OpenAPIFirstApp
+import routes
+
+app = OpenAPIFirstApp(
+    openapi_path="openapi.yaml",
+    routes_module=routes,
+    title="CRUD Example Service",
+)

openapi_first/templates/crud_app/openapi.yaml

@@ -0,0 +1,115 @@
+openapi: 3.0.3
+info:
+  title: CRUD Example Service
+  version: "1.0.0"
+  description: Minimal OpenAPI-first CRUD service with in-memory mock data.
+
+paths:
+  /items:
+    get:
+      operationId: list_items
+      summary: List all items
+      responses:
+        "200":
+          description: List of items
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/Item"
+
+    post:
+      operationId: create_item
+      summary: Create a new item
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ItemCreate"
+      responses:
+        "201":
+          description: Item created
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+
+  /items/{item_id}:
+    get:
+      operationId: get_item
+      summary: Get item by ID
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      responses:
+        "200":
+          description: Item found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+
+    put:
+      operationId: update_item
+      summary: Update an item
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ItemCreate"
+      responses:
+        "200":
+          description: Item updated
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+
+    delete:
+      operationId: delete_item
+      summary: Delete an item
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      responses:
+        "204":
+          description: Item deleted
+
+components:
+  schemas:
+    Item:
+      type: object
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+        price:
+          type: number
+          format: float
+      required: [id, name, price]
+
+    ItemCreate:
+      type: object
+      properties:
+        name:
+          type: string
+        price:
+          type: number
+          format: float
+      required: [name, price]

openapi_first/templates/crud_app/routes.py

@@ -0,0 +1,50 @@
+"""
+CRUD route handlers bound via OpenAPI operationId.
+
+These handlers explicitly control HTTP status codes to ensure
+runtime behavior matches the OpenAPI contract.
+"""
+
+from fastapi import Response, HTTPException
+
+from data import (
+    list_items as _list_items,
+    get_item as _get_item,
+    create_item as _create_item,
+    update_item as _update_item,
+    delete_item as _delete_item,
+)
+
+
+def list_items():
+    return _list_items()
+
+
+def get_item(item_id: int):
+    try:
+        return _get_item(item_id)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+
+def create_item(payload: dict, response: Response):
+    item = _create_item(payload)
+    response.status_code = 201
+    return item
+
+
+def update_item(item_id: int, payload: dict):
+    try:
+        return _update_item(item_id, payload)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+
+def delete_item(item_id: int, response: Response):
+    try:
+        _delete_item(item_id)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    response.status_code = 204
+    return None

openapi_first/templates/crud_app/test_crud_app.py

@@ -0,0 +1,116 @@
+"""
+End-to-end tests for the OpenAPI-first CRUD example app.
+
+These tests validate that all CRUD operations behave correctly
+against the in-memory mock data store.
+
+The tests assume:
+- OpenAPI-first route binding
+- In-memory storage (no persistence guarantees)
+- Deterministic behavior in a single process
+"""
+
+from fastapi.testclient import TestClient
+
+from main import app
+from openapi_first.loader import load_openapi
+from openapi_first.client import OpenAPIClient
+
+
+client = TestClient(app)
+spec = load_openapi("openapi.yaml")
+client = OpenAPIClient(
+    spec=spec,
+    base_url="http://testserver",
+    client=client,
+)
+
+
+def test_list_items_initial():
+    """Initial items should be present."""
+    response = client.list_items()
+    assert response.status_code == 200
+
+    data = response.json()
+    assert isinstance(data, list)
+    assert len(data) >= 2
+
+    ids = {item["id"] for item in data}
+    assert 1 in ids
+    assert 2 in ids
+
+
+def test_get_item():
+    """Existing item should be retrievable by ID."""
+    response = client.get_item(
+        path_params={"item_id": 1}
+    )
+    assert response.status_code == 200
+
+    item = response.json()
+    assert item["id"] == 1
+    assert "name" in item
+    assert "price" in item
+
+
+def test_create_item():
+    """Creating a new item should return the created entity."""
+    payload = {
+        "name": "Orange",
+        "price": 0.8,
+    }
+
+    response = client.create_item(
+        body=payload
+    )
+    assert response.status_code == 201
+
+    item = response.json()
+    assert "id" in item
+    assert item["name"] == payload["name"]
+    assert item["price"] == payload["price"]
+
+    # Verify it appears in list
+    list_response = client.list_items()
+    ids = {i["id"] for i in list_response.json()}
+    assert item["id"] in ids
+
+
+def test_update_item():
+    """Updating an item should replace its values."""
+    payload = {
+        "name": "Green Apple",
+        "price": 0.6,
+    }
+
+    response = client.update_item(
+        path_params={"item_id": 1},
+        body=payload,
+    )
+    assert response.status_code == 200
+
+    item = response.json()
+    assert item["id"] == 1
+    assert item["name"] == payload["name"]
+    assert item["price"] == payload["price"]
+
+    # Verify persisted update
+    get_response = client.get_item(
+        path_params={"item_id": 1}
+    )
+    updated = get_response.json()
+    assert updated["name"] == payload["name"]
+    assert updated["price"] == payload["price"]
+
+
+def test_delete_item():
+    """Deleting an item should remove it from the store."""
+    response = client.delete_item(
+        path_params={"item_id": 2}
+    )
+    assert response.status_code == 204
+
+    # Verify deletion
+    list_response = client.list_items()
+    ids = {item["id"] for item in list_response.json()}
+    assert 2 not in ids

openapi_first/templates/model_app/data.py

@@ -0,0 +1,44 @@
+"""
+In-memory data store using Pydantic models.
+
+This module is NOT thread-safe and is intended for demos and scaffolds only.
+"""
+
+from typing import Dict
+
+from models import Item, ItemCreate
+
+_items: Dict[int, Item] = {
+    1: Item(id=1, name="Apple", price=0.5),
+    2: Item(id=2, name="Banana", price=0.3),
+}
+
+_next_id = 3
+
+
+def list_items() -> list[Item]:
+    return list(_items.values())
+
+
+def get_item(item_id: int) -> Item:
+    return _items[item_id]
+
+
+def create_item(payload: ItemCreate) -> Item:
+    global _next_id
+    item = Item(id=_next_id, **payload.model_dump())
+    _items[_next_id] = item
+    _next_id += 1
+    return item
+
+
+def update_item(item_id: int, payload: ItemCreate) -> Item:
+    if item_id not in _items:
+        raise KeyError(item_id)
+    item = Item(id=item_id, **payload.model_dump())
+    _items[item_id] = item
+    return item
+
+
+def delete_item(item_id: int) -> None:
+    del _items[item_id]

openapi_first/templates/model_app/main.py

@@ -0,0 +1,8 @@
+from openapi_first.app import OpenAPIFirstApp
+import routes
+
+app = OpenAPIFirstApp(
+    openapi_path="openapi.yaml",
+    routes_module=routes,
+    title="Model CRUD Example Service",
+)

openapi_first/templates/model_app/models.py

@@ -0,0 +1,18 @@
+"""
+Pydantic domain models for the CRUD example.
+"""
+
+from pydantic import BaseModel
+
+
+class ItemBase(BaseModel):
+    name: str
+    price: float
+
+
+class ItemCreate(ItemBase):
+    pass
+
+
+class Item(ItemBase):
+    id: int

openapi_first/templates/model_app/openapi.yaml

@@ -0,0 +1,116 @@
+openapi: 3.0.3
+info:
+  title: Model CRUD Example Service
+  version: "1.0.0"
+  description: OpenAPI-first CRUD service with Pydantic models.
+
+paths:
+  /items:
+    get:
+      operationId: list_items
+      responses:
+        "200":
+          description: List of items
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/Item"
+
+    post:
+      operationId: create_item
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ItemCreate"
+      responses:
+        "201":
+          description: Item created
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+
+  /items/{item_id}:
+    get:
+      operationId: get_item
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      responses:
+        "200":
+          description: Item found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+        "404":
+          description: Item not found
+
+    put:
+      operationId: update_item
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ItemCreate"
+      responses:
+        "200":
+          description: Item updated
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Item"
+        "404":
+          description: Item not found
+
+    delete:
+      operationId: delete_item
+      parameters:
+        - name: item_id
+          in: path
+          required: true
+          schema:
+            type: integer
+      responses:
+        "204":
+          description: Item deleted
+        "404":
+          description: Item not found
+
+components:
+  schemas:
+    Item:
+      type: object
+      required: [id, name, price]
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+        price:
+          type: number
+          format: float
+
+    ItemCreate:
+      type: object
+      required: [name, price]
+      properties:
+        name:
+          type: string
+        price:
+          type: number
+          format: float

openapi_first/templates/model_app/routes.py

@@ -0,0 +1,48 @@
+"""
+CRUD route handlers bound via OpenAPI operationId.
+"""
+
+from fastapi import Response, HTTPException
+
+from models import ItemCreate
+from data import (
+    list_items as _list_items,
+    get_item as _get_item,
+    create_item as _create_item,
+    update_item as _update_item,
+    delete_item as _delete_item,
+)
+
+
+def list_items():
+    return _list_items()
+
+
+def get_item(item_id: int):
+    try:
+        return _get_item(item_id)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+
+def create_item(payload: ItemCreate, response: Response):
+    item = _create_item(payload)
+    response.status_code = 201
+    return item
+
+
+def update_item(item_id: int, payload: ItemCreate):
+    try:
+        return _update_item(item_id, payload)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+
+def delete_item(item_id: int, response: Response):
+    try:
+        _delete_item(item_id)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    response.status_code = 204
+    return None

openapi_first/templates/model_app/test_model_app.py

@@ -0,0 +1,117 @@
+"""
+End-to-end tests for the OpenAPI-first model CRUD example app.
+
+These tests validate that all CRUD operations behave correctly
+against the in-memory mock data store using Pydantic models.
+
+The tests assume:
+- OpenAPI-first route binding
+- Pydantic model validation
+- In-memory storage (no persistence guarantees)
+- Deterministic behavior in a single process
+"""
+
+from fastapi.testclient import TestClient
+
+from main import app
+from openapi_first.loader import load_openapi
+from openapi_first.client import OpenAPIClient
+
+
+client = TestClient(app)
+spec = load_openapi("openapi.yaml")
+client = OpenAPIClient(
+    spec=spec,
+    base_url="http://testserver",
+    client=client,
+)
+
+
+def test_list_items_initial():
+    """Initial items should be present."""
+    response = client.list_items()
+    assert response.status_code == 200
+
+    data = response.json()
+    assert isinstance(data, list)
+    assert len(data) >= 2
+
+    ids = {item["id"] for item in data}
+    assert 1 in ids
+    assert 2 in ids
+
+
+def test_get_item():
+    """Existing item should be retrievable by ID."""
+    response = client.get_item(
+        path_params={"item_id": 1}
+    )
+    assert response.status_code == 200
+
+    item = response.json()
+    assert item["id"] == 1
+    assert isinstance(item["name"], str)
+    assert isinstance(item["price"], float)
+
+
+def test_create_item():
+    """Creating a new item should return the created entity."""
+    payload = {
+        "name": "Orange",
+        "price": 0.8,
+    }
+
+    response = client.create_item(
+        body=payload
+    )
+    assert response.status_code == 201
+
+    item = response.json()
+    assert "id" in item
+    assert item["name"] == payload["name"]
+    assert item["price"] == payload["price"]
+
+    # Verify it appears in list
+    list_response = client.list_items()
+    ids = {i["id"] for i in list_response.json()}
+    assert item["id"] in ids
+
+
+def test_update_item():
+    """Updating an item should replace its values."""
+    payload = {
+        "name": "Green Apple",
+        "price": 0.6,
+    }
+
+    response = client.update_item(
+        path_params={"item_id": 1},
+        body=payload,
+    )
+    assert response.status_code == 200
+
+    item = response.json()
+    assert item["id"] == 1
+    assert item["name"] == payload["name"]
+    assert item["price"] == payload["price"]
+
+    # Verify persisted update
+    get_response = client.get_item(
+        path_params={"item_id": 1}
+    )
+    updated = get_response.json()
+    assert updated["name"] == payload["name"]
+    assert updated["price"] == payload["price"]
+
+
+def test_delete_item():
+    """Deleting an item should remove it from the store."""
+    response = client.delete_item(
+        path_params={"item_id": 2}
+    )
+    assert response.status_code == 204
+
+    # Verify deletion
+    list_response = client.list_items()
+    ids = {item["id"] for item in list_response.json()}
+    assert 2 not in ids

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "openapi-first"
-version = "0.0.1"
+version = "0.0.3"
 description = "Strict OpenAPI-first application bootstrap for FastAPI."
 readme = "README.md"
 requires-python = ">=3.10"

requirements.txt

@@ -1,7 +1,9 @@
 fastapi==0.128.0,
-openapi-spec-validator==0.7.2,
-pyyaml==6.0.3,
+openapi-spec-validator==0.7.2
+pyyaml==6.0.3
 uvicorn==0.40.0
+pydantic==2.12.5
+httpx==0.28.1
 
 # Test Packages
 pytest==7.4.0