feat(auth): M3 §10 绑微信按默认替换展示昵称头像(共享 helper 接两路径)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_withdraw.py

@@ -312,6 +312,94 @@ def test_bind_rejects_openid_already_bound(client, monkeypatch) -> None:
     assert r.status_code == 409, r.text
 
 
+# ===== §10 绑微信时展示身份回填规则 =====
+
+def test_bind_replaces_default_nickname_and_null_avatar(client, monkeypatch) -> None:
+    """§10-A: 全默认(昵称=系统默认,头像=null) → 绑微信后两个展示字段都替换为微信值。"""
+    monkeypatch.setattr(
+        "app.integrations.wxpay.code_to_userinfo",
+        lambda code: {"openid": "openid_s10_a", "nickname": "微信昵称A", "avatar_url": "https://x/a.png", "raw": {}},
+    )
+    token = _login(client, "13800003001")
+    r = client.post("/api/v1/wallet/bind-wechat", json={"code": "c"}, headers=_auth(token))
+    assert r.status_code == 200, r.text
+
+    r = client.get("/api/v1/auth/me", headers=_auth(token))
+    assert r.status_code == 200, r.text
+    body = r.json()
+    assert body["nickname"] == "微信昵称A"
+    assert body["avatar_url"] == "https://x/a.png"
+
+
+def test_bind_keeps_customized_nickname(client, monkeypatch) -> None:
+    """§10-B: 用户已改过昵称 → 绑微信后昵称保留,但 null 头像仍替换为微信头像。"""
+    monkeypatch.setattr(
+        "app.integrations.wxpay.code_to_userinfo",
+        lambda code: {"openid": "openid_s10_b", "nickname": "微信昵称B", "avatar_url": "https://x/b.png", "raw": {}},
+    )
+    token = _login(client, "13800003002")
+    # 先把昵称改成非默认值
+    r = client.patch(
+        "/api/v1/user/profile", json={"nickname": "我的名字"}, headers=_auth(token)
+    )
+    assert r.status_code == 200, r.text
+
+    r = client.post("/api/v1/wallet/bind-wechat", json={"code": "c"}, headers=_auth(token))
+    assert r.status_code == 200, r.text
+
+    r = client.get("/api/v1/auth/me", headers=_auth(token))
+    body = r.json()
+    assert body["nickname"] == "我的名字"       # 保留自定义昵称
+    assert body["avatar_url"] == "https://x/b.png"  # null 头像被微信头像替换
+
+
+def test_bind_keeps_customized_avatar(client, monkeypatch) -> None:
+    """§10-C: 已有自定义头像 → 绑微信后头像保留,但默认昵称替换为微信昵称。"""
+    monkeypatch.setattr(
+        "app.integrations.wxpay.code_to_userinfo",
+        lambda code: {"openid": "openid_s10_c", "nickname": "微信昵称C", "avatar_url": "https://x/c.png", "raw": {}},
+    )
+    token = _login(client, "13800003003")
+    phone = "13800003003"
+    # 直接用 DB 给用户写入自定义头像(保持默认昵称)
+    db = SessionLocal()
+    try:
+        user = db.execute(select(User).where(User.phone == phone)).scalar_one()
+        user.avatar_url = "https://custom/av.png"
+        db.commit()
+    finally:
+        db.close()
+
+    r = client.post("/api/v1/wallet/bind-wechat", json={"code": "c"}, headers=_auth(token))
+    assert r.status_code == 200, r.text
+
+    r = client.get("/api/v1/auth/me", headers=_auth(token))
+    body = r.json()
+    assert body["nickname"] == "微信昵称C"           # 默认昵称被替换
+    assert body["avatar_url"] == "https://custom/av.png"  # 自定义头像保留
+
+
+def test_bind_wechat_empty_keeps_default(client, monkeypatch) -> None:
+    """§10-D: 微信侧 nickname/avatar 均为 None → 不覆盖,展示字段维持原默认值。"""
+    monkeypatch.setattr(
+        "app.integrations.wxpay.code_to_userinfo",
+        lambda code: {"openid": "openid_s10_d", "nickname": None, "avatar_url": None, "raw": {}},
+    )
+    token = _login(client, "13800003004")
+
+    r = client.get("/api/v1/auth/me", headers=_auth(token))
+    original_nickname = r.json()["nickname"]  # 系统分配的默认昵称
+    assert original_nickname.startswith("用户")
+
+    r = client.post("/api/v1/wallet/bind-wechat", json={"code": "c"}, headers=_auth(token))
+    assert r.status_code == 200, r.text
+
+    r = client.get("/api/v1/auth/me", headers=_auth(token))
+    body = r.json()
+    assert body["nickname"] == original_nickname  # 默认昵称不变
+    assert body["avatar_url"] is None             # 头像仍为 null
+
+
 def test_withdraw_reject_refunds(client, monkeypatch) -> None:
     """管理员审核拒绝 → 退回现金 + 单 rejected + 理由写入 fail_reason(用户可见)。"""
     monkeypatch.setattr("app.integrations.wxpay.code_to_userinfo", lambda code: {"openid": "openid_reject", "nickname": None, "avatar_url": None, "raw": {}})