Login Operatore con nome + PIN: elenco nomi, tastierino, route login-pin (#59)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docker-compose.dev.yml

@@ -14,6 +14,7 @@ services:
       --authentication-policy=mysql_native_password
       --character-set-server=utf8mb4
       --collation-server=utf8mb4_unicode_ci
+      --default-time-zone=+00:00
     healthcheck:
       test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
       interval: 10s

docker-compose.yml

@@ -14,6 +14,7 @@ services:
       --authentication-policy=mysql_native_password
       --character-set-server=utf8mb4
       --collation-server=utf8mb4_unicode_ci
+      --default-time-zone=+00:00
     healthcheck:
       test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
       interval: 10s

src/backend/api/middleware/api_key.py

@@ -9,7 +9,8 @@ from src.backend.database import get_db
 from src.backend.config import settings
 from src.backend.models.orm.api_key import ApiKey
 from src.backend.models.orm.user import User
-from src.backend.services.auth_service import hash_api_key, utcnow
+from src.backend.services.auth_service import hash_api_key
+from src.backend.utils.tempo import utcnow
 
 _RENEW_INTERVAL = timedelta(minutes=5)
 

src/backend/api/routers/measurements.py

@@ -2,6 +2,8 @@
 import csv
 import io
 from datetime import datetime
+from src.backend.models.api.tipi import UtcNaiveInput
+from src.backend.utils.tempo import as_utc_naive, iso_utc, to_local, utcnow
 
 from fastapi import APIRouter, Depends, HTTPException, Query, status
 from fastapi.responses import StreamingResponse
@@ -232,8 +234,8 @@ async def get_measurements(
     measured_by: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     pass_fail: str | None = Query(None, pattern="^(pass|warning|fail)$"),
     production_run_id: int | None = Query(None, gt=0),
     page: int = Query(1, ge=1),
@@ -290,8 +292,8 @@ async def export_measurements_csv(
     measured_by: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     pass_fail: str | None = Query(None, pattern="^(pass|warning|fail)$"),
     user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
@@ -372,7 +374,7 @@ async def export_measurements_csv(
             neutralise_csv_cell(m.lot_number or ""),
             neutralise_csv_cell(m.serial_number or ""),
             m.input_method,
-            m.measured_at.isoformat(),
+            iso_utc(m.measured_at),
             m.synced_to_csv,
         ])
 
@@ -382,6 +384,6 @@ async def export_measurements_csv(
         iter([output.getvalue()]),
         media_type="text/csv",
         headers={
-            "Content-Disposition": f"attachment; filename=measurements_{datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
+            "Content-Disposition": f"attachment; filename=measurements_{to_local(utcnow()).strftime('%Y%m%d_%H%M%S')}.csv"
         },
     )

src/backend/api/routers/reports.py

@@ -1,5 +1,5 @@
 """Reports router — PDF report generation endpoints for Metrologist."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcNaiveInput
 
 from fastapi import APIRouter, Depends, HTTPException, Query, status
 from fastapi.responses import Response
@@ -18,8 +18,8 @@ async def download_spc_report(
     recipe_id: int = Query(...),
     subtask_id: int = Query(...),
     version_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
@@ -52,8 +52,8 @@ async def download_measurement_report(
     recipe_id: int = Query(...),
     subtask_id: int | None = Query(None),
     version_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),

src/backend/api/routers/setup.py

@@ -6,6 +6,7 @@ NOT protected by API Key auth (standalone access).
 import hmac
 import random
 from datetime import datetime, timedelta
+from src.backend.utils.tempo import iso_utc, utcnow
 from pathlib import Path
 
 from alembic import command
@@ -555,7 +556,7 @@ async def seed_demo_data(body: PasswordBody):
             tec_user = created_users[2]  # tec1
             lot_numbers = ["LOT-2025-001", "LOT-2025-002", "LOT-2025-003", "LOT-2025-004"]
             serial_numbers = [f"SN-{i:04d}" for i in range(1, 13)]
-            base_date = datetime.now()
+            base_date = utcnow()
 
             all_subtasks = subtasks_1 + subtasks_2
             measurements_created = 0
@@ -603,8 +604,8 @@ async def list_users(body: PasswordBody):
                     "roles": u.roles or [],
                     "is_admin": u.is_admin,
                     "active": u.active,
-                    "created_at": u.created_at.isoformat() if u.created_at else None,
-                    "last_login": u.last_login.isoformat() if u.last_login else None,
+                    "created_at": iso_utc(u.created_at) or None,
+                    "last_login": iso_utc(u.last_login) or None,
                 }
                 for u in users
             ],

src/backend/api/routers/statistics.py

@@ -1,5 +1,6 @@
 """Statistics router - SPC endpoints for Metrologist dashboard."""
 from datetime import datetime
+from src.backend.models.api.tipi import UtcNaiveInput
 
 from fastapi import APIRouter, Depends, HTTPException, Query, status
 from sqlalchemy import and_, select
@@ -100,8 +101,8 @@ async def get_summary(
     recipe_id: int = Query(...),
     version_id: int | None = Query(None),
     subtask_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
@@ -122,8 +123,8 @@ async def get_capability(
     recipe_id: int = Query(...),
     subtask_id: int = Query(...),
     version_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
@@ -145,8 +146,8 @@ async def get_control_chart(
     recipe_id: int = Query(...),
     subtask_id: int = Query(...),
     version_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),
@@ -172,8 +173,8 @@ async def get_histogram(
     recipe_id: int = Query(...),
     subtask_id: int = Query(...),
     version_id: int | None = Query(None),
-    date_from: datetime | None = Query(None),
-    date_to: datetime | None = Query(None),
+    date_from: UtcNaiveInput = Query(None),
+    date_to: UtcNaiveInput = Query(None),
     operator_id: int | None = Query(None),
     lot_number: str | None = Query(None),
     serial_number: str | None = Query(None),

src/backend/config.py

@@ -28,6 +28,9 @@ class Settings(BaseSettings):
     db_user: str = "tmflow"
     db_password: str = _DEFAULT_DB_PASSWORD
 
+    # Presentation time zone (DB is UTC, #42)
+    display_timezone: str = "Europe/Rome"
+
     # Server
     server_host: str = "0.0.0.0"
     server_port: int = 8000

src/backend/models/api/measurement.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for Measurement operations."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime, UtcNaiveInput
 from typing import Optional
 
 from pydantic import BaseModel, ConfigDict, Field
@@ -54,8 +54,8 @@ class MeasurementResponse(BaseModel):
     # Who let this value stand, when it was out of tolerance. Null on a value in
     # tolerance - and on one that is not and is still waiting for an answer.
     supervisor_id: Optional[int] = None
-    authorised_at: Optional[datetime] = None
-    measured_at: datetime
+    authorised_at: Optional[UtcDateTime] = None
+    measured_at: UtcDateTime
     synced_to_csv: bool
 
 
@@ -97,7 +97,7 @@ class CycleMeasurementResponse(BaseModel):
     subtask_id: int
     value: float
     pass_fail: str
-    measured_at: datetime
+    measured_at: UtcDateTime
 
 
 class CurrentCycleResponse(BaseModel):
@@ -114,8 +114,8 @@ class MeasurementQuery(BaseModel):
     measured_by: Optional[int] = None
     lot_number: Optional[str] = None
     serial_number: Optional[str] = None
-    date_from: Optional[datetime] = None
-    date_to: Optional[datetime] = None
+    date_from: UtcNaiveInput = None
+    date_to: UtcNaiveInput = None
     pass_fail: Optional[str] = Field(None, pattern="^(pass|warning|fail)$")
     page: int = Field(1, ge=1)
     per_page: int = Field(50, ge=1, le=500)

src/backend/models/api/production.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for production runs and their events."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime
 from typing import Literal, Optional
 
 from pydantic import BaseModel, ConfigDict, Field
@@ -21,7 +21,7 @@ class ProductionEventResponse(BaseModel):
     supervisor_id: Optional[int]
     task_id: Optional[int] = None
     note: Optional[str]
-    created_at: datetime
+    created_at: UtcDateTime
 
 
 class ProductionRunResponse(BaseModel):
@@ -36,11 +36,11 @@ class ProductionRunResponse(BaseModel):
     serial_number: Optional[str]
     status: str
     measurement_interval_minutes: Optional[int]
-    next_measurement_at: Optional[datetime]
+    next_measurement_at: Optional[UtcDateTime]
     cycle_count: int
-    started_at: datetime
-    paused_at: Optional[datetime]
-    closed_at: Optional[datetime]
+    started_at: UtcDateTime
+    paused_at: Optional[UtcDateTime]
+    closed_at: Optional[UtcDateTime]
     closed_by: Optional[int]
     statistics_path: Optional[str] = None
 
@@ -49,7 +49,7 @@ class ProductionRunResponse(BaseModel):
     # overdue is a fact the operator must see, not deduce.
     seconds_to_next_measurement: Optional[int] = None
     overdue: bool = False
-    server_time: Optional[datetime] = None
+    server_time: Optional[UtcDateTime] = None
 
     # The measurement tasks of this run's version, in execution order. The client
     # needs them to bring the operator back to the measurement when the interval

src/backend/models/api/recipe.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for Recipe and RecipeVersion operations."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime
 from typing import Optional, TYPE_CHECKING
 
 from pydantic import BaseModel, ConfigDict, Field
@@ -51,7 +51,7 @@ class RecipeVersionResponse(BaseModel):
     version_number: int
     is_current: bool
     created_by: int
-    created_at: datetime
+    created_at: UtcDateTime
     change_notes: Optional[str] = None
     tasks: list["TaskResponse"] = []
 
@@ -72,7 +72,7 @@ class RecipeResponse(BaseModel):
     requires_serial: bool = False
     allow_manual_input: bool = False
     created_by: int
-    created_at: datetime
+    created_at: UtcDateTime
     active: bool
     current_version: Optional[RecipeVersionResponse] = None
 

src/backend/models/api/station.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for Station and StationRecipeAssignment."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime
 from typing import Optional
 
 from pydantic import BaseModel, ConfigDict, Field
@@ -29,7 +29,7 @@ class StationResponse(BaseModel):
     notes: Optional[str]
     active: bool
     created_by: int
-    created_at: datetime
+    created_at: UtcDateTime
 
 
 class StationRecipeAssignmentCreate(BaseModel):
@@ -42,7 +42,7 @@ class StationRecipeAssignmentResponse(BaseModel):
     station_id: int
     recipe_id: int
     assigned_by: int
-    assigned_at: datetime
+    assigned_at: UtcDateTime
 
 
 class RecipeSummary(BaseModel):

src/backend/models/api/statistics.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for SPC statistics responses."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime, UtcNaiveInput
 from typing import Optional
 
 from pydantic import BaseModel, Field
@@ -10,8 +10,8 @@ class StatisticsQuery(BaseModel):
     recipe_id: int
     version_id: Optional[int] = None
     subtask_id: Optional[int] = None
-    date_from: Optional[datetime] = None
-    date_to: Optional[datetime] = None
+    date_from: UtcNaiveInput = None
+    date_to: UtcNaiveInput = None
     operator_id: Optional[int] = None
     lot_number: Optional[str] = None
     serial_number: Optional[str] = None
@@ -20,7 +20,7 @@ class StatisticsQuery(BaseModel):
 class ControlChartData(BaseModel):
     """Data for X-bar/R control chart."""
     values: list[float]
-    timestamps: list[datetime]
+    timestamps: list[UtcDateTime]
     mean: float
     ucl: float  # Upper Control Limit
     lcl: float  # Lower Control Limit
@@ -60,7 +60,7 @@ class CapabilityData(BaseModel):
 
 class TrendData(BaseModel):
     """Temporal trend data for capability indices."""
-    dates: list[datetime]
+    dates: list[UtcDateTime]
     cpk_values: list[Optional[float]]
     ppk_values: list[Optional[float]]
     n_per_period: list[int]

src/backend/models/api/tipi.py

@@ -0,0 +1,14 @@
+"""Shared Pydantic types for datetimes (#42): UTC in the DB, explicit +00:00 on the wire."""
+from datetime import datetime
+from typing import Annotated, Optional
+
+from pydantic import AfterValidator, PlainSerializer
+
+from src.backend.utils.tempo import as_utc_naive, to_utc_aware
+
+UtcDateTime = Annotated[
+    datetime, PlainSerializer(lambda v: to_utc_aware(v).isoformat(), return_type=str)
+]
+
+# Input: aware values are converted to UTC naive, naive is taken as UTC.
+UtcNaiveInput = Annotated[Optional[datetime], AfterValidator(as_utc_naive)]

src/backend/models/api/user.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for User operations."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime
 from typing import Optional
 
 from pydantic import BaseModel, ConfigDict, Field
@@ -48,8 +48,8 @@ class UserResponse(BaseModel):
     language_pref: str
     theme_pref: str
     active: bool
-    created_at: datetime
-    last_login: Optional[datetime] = None
+    created_at: UtcDateTime
+    last_login: Optional[UtcDateTime] = None
 
 
 class UserPasswordChange(BaseModel):

src/backend/models/api/vision.py

@@ -1,5 +1,5 @@
 """Pydantic schemas for the vision execution response."""
-from datetime import datetime
+from src.backend.models.api.tipi import UtcDateTime
 
 from pydantic import BaseModel, ConfigDict
 
@@ -28,4 +28,4 @@ class VisionReferenceImageResponse(BaseModel):
     note: str | None = None
     station_id: int | None = None
     device_code: str | None = None
-    acquired_at: datetime
+    acquired_at: UtcDateTime

src/backend/services/auth_service.py

@@ -1,7 +1,8 @@
 """Authentication service - password hashing, API key management."""
 import hashlib
 import secrets
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta
+from src.backend.utils.tempo import utcnow
 
 import bcrypt
 from fastapi import HTTPException, status
@@ -78,11 +79,6 @@ async def authorise_supervisor(db: AsyncSession, username: str, password: str) -
     return supervisor
 
 
-def utcnow() -> datetime:
-    """Naive UTC now (the whole DB moves to naive UTC, #42)."""
-    return datetime.now(timezone.utc).replace(tzinfo=None)
-
-
 def hash_api_key(key: str) -> str:
     """SHA-256 hex digest of an API key; this is all the DB ever stores."""
     return hashlib.sha256(key.encode("utf-8")).hexdigest()

src/backend/services/measurement_service.py

@@ -1,6 +1,7 @@
 """Measurement service - pass/fail calculation, data storage."""
 import math
 from datetime import datetime
+from src.backend.utils.tempo import utcnow
 from decimal import Decimal
 from typing import TYPE_CHECKING
 
@@ -343,7 +344,7 @@ async def authorise_measurement(
 ) -> Measurement:
     """Let an out-of-tolerance value stand, on the supervisor's name."""
     measurement.supervisor_id = supervisor.id
-    measurement.authorised_at = datetime.now()
+    measurement.authorised_at = utcnow()
     await db.flush()
     await db.refresh(measurement)
     return measurement

src/backend/services/production_export_service.py

@@ -14,6 +14,7 @@ import csv
 import io
 import logging
 from datetime import datetime
+from src.backend.utils.tempo import iso_utc, to_local, utcnow
 from pathlib import Path
 
 from sqlalchemy import select, update
@@ -169,9 +170,9 @@ async def build_statistics_csv(db: AsyncSession, run: ProductionRun) -> str:
             measurement.input_method,
             "" if measurement.input_duration_ms is None else measurement.input_duration_ms,
             measurement.measured_by,
-            measurement.measured_at.isoformat() if measurement.measured_at else "",
+            iso_utc(measurement.measured_at),
             measurement.supervisor_id or "",
-            measurement.authorised_at.isoformat() if measurement.authorised_at else "",
+            iso_utc(measurement.authorised_at),
         ])
 
     return output.getvalue()
@@ -191,7 +192,7 @@ async def export_run_statistics(db: AsyncSession, run: ProductionRun) -> str | N
     directory = Path(settings.upload_path) / EXPORT_SUBDIR
     directory.mkdir(parents=True, exist_ok=True)
 
-    stamp = (run.closed_at or datetime.now()).strftime("%Y%m%d_%H%M%S")
+    stamp = to_local(run.closed_at or utcnow()).strftime("%Y%m%d_%H%M%S")
     filename = f"production_{run.id}_{stamp}.csv"
     # A large run's file can take a moment to write: off the event loop, so
     # closing one run does not stall every other request being served.

src/backend/services/production_service.py

@@ -14,6 +14,7 @@ the countdown would be off by the UTC offset. The number is the contract; the
 timestamp is only there for the audit trail.
 """
 from datetime import datetime, timedelta
+from src.backend.utils.tempo import utcnow
 from typing import Optional
 
 from fastapi import HTTPException, status
@@ -34,10 +35,10 @@ from src.backend.services import (
 def _now() -> datetime:
     """Single source of time for runs.
 
-    Naive local time, matching what the database writes for ``func.now()`` defaults,
+    Naive UTC, matching what the database writes for ``func.now()`` defaults,
     so a run's started_at and its deadline are comparable.
     """
-    return datetime.now()
+    return utcnow()
 
 
 # ---------------------------------------------------------------------------

src/backend/services/report_service.py

@@ -2,6 +2,7 @@
 import asyncio
 import base64
 from datetime import datetime
+from src.backend.utils.tempo import to_local, utcnow
 from pathlib import Path
 
 import plotly.graph_objects as go
@@ -32,6 +33,11 @@ _jinja_env = Environment(
 )
 
 
+def _giorno_locale(dt: datetime) -> str:
+    """UTC naive filter bound -> local calendar day (YYYY-MM-DD)."""
+    return to_local(dt).strftime("%Y-%m-%d")
+
+
 async def _query_measurements(
     db: AsyncSession,
     recipe_id: int,
@@ -323,9 +329,9 @@ async def generate_spc_report(
     if version_id:
         filters_desc.append(f"Version: {version_id}")
     if date_from:
-        filters_desc.append(f"From: {date_from.strftime('%Y-%m-%d')}")
+        filters_desc.append(f"From: {_giorno_locale(date_from)}")
     if date_to:
-        filters_desc.append(f"To: {date_to.strftime('%Y-%m-%d')}")
+        filters_desc.append(f"To: {_giorno_locale(date_to)}")
     if lot_number:
         filters_desc.append(f"Lot: {lot_number}")
     if serial_number:
@@ -342,7 +348,7 @@ async def generate_spc_report(
         control_chart_svg=control_chart_svg,
         histogram_svg=histogram_svg,
         filters_desc=filters_desc,
-        generated_at=datetime.now(),
+        generated_at=to_local(utcnow()),
         n_measurements=len(measurements),
     )
 
@@ -395,7 +401,7 @@ async def generate_measurement_report(
             "value": f"{float(m.value):.4f}",
             "unit": st_info.get("unit", "mm"),
             "pass_fail": m.pass_fail,
-            "measured_at": m.measured_at.strftime("%Y-%m-%d %H:%M"),
+            "measured_at": to_local(m.measured_at).strftime("%Y-%m-%d %H:%M"),
             "operator": operator_map.get(m.measured_by, f"ID {m.measured_by}"),
             "lot_number": m.lot_number or "—",
             "serial_number": m.serial_number or "—",
@@ -414,9 +420,9 @@ async def generate_measurement_report(
     if version_id:
         filters_desc.append(f"Version: {version_id}")
     if date_from:
-        filters_desc.append(f"From: {date_from.strftime('%Y-%m-%d')}")
+        filters_desc.append(f"From: {_giorno_locale(date_from)}")
     if date_to:
-        filters_desc.append(f"To: {date_to.strftime('%Y-%m-%d')}")
+        filters_desc.append(f"To: {_giorno_locale(date_to)}")
     if lot_number:
         filters_desc.append(f"Lot: {lot_number}")
     if serial_number:
@@ -430,7 +436,7 @@ async def generate_measurement_report(
         rows=rows,
         summary=summary,
         filters_desc=filters_desc,
-        generated_at=datetime.now(),
+        generated_at=to_local(utcnow()),
         n_measurements=len(measurements),
     )
 

src/backend/tests/test_tempo.py

@@ -0,0 +1,113 @@
+"""UTC in the DB, explicit +00:00 on the wire, local time only on presentation (#42)."""
+from datetime import datetime, timezone
+from unittest.mock import patch
+
+from httpx import AsyncClient
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from src.backend.models.orm.user import User
+from src.backend.services import report_service
+from src.backend.tests.conftest import auth_headers, create_test_recipe
+from src.backend.utils.tempo import as_utc_naive, to_local, utcnow
+
+
+def test_utcnow_naive_and_close_to_utc():
+    now = utcnow()
+    assert now.tzinfo is None
+    delta = datetime.now(timezone.utc).replace(tzinfo=None) - now
+    assert abs(delta.total_seconds()) < 5
+
+
+def test_as_utc_naive():
+    parsed = datetime.fromisoformat("2026-10-06T10:00:00+02:00")
+    assert as_utc_naive(parsed) == datetime(2026, 10, 6, 8, 0)
+    assert as_utc_naive(parsed).tzinfo is None
+    naive = datetime(2026, 10, 6, 8, 0)
+    assert as_utc_naive(naive) is naive
+    assert as_utc_naive(None) is None
+
+
+def test_to_local_is_rome():
+    assert to_local(datetime(2026, 10, 6, 8, 0)).strftime("%H:%M %z") == "10:00 +0200"
+    assert to_local(datetime(2026, 1, 6, 8, 0)).strftime("%H:%M %z") == "09:00 +0100"
+
+
+async def _make_measurement(client, user, recipe_id) -> None:
+    tasks = (await client.get(f"/api/recipes/{recipe_id}/tasks", headers=auth_headers(user))).json()
+    await client.post(
+        "/api/measurements/",
+        headers=auth_headers(user),
+        json={
+            "subtask_id": tasks[0]["subtasks"][0]["id"],
+            "version_id": tasks[0]["version_id"],
+            "value": 10.0,
+        },
+    )
+
+
+async def test_api_datetimes_carry_utc_offset_and_filter_equivalence(
+    client: AsyncClient,
+    measurement_tec_user: User,
+    metrologist_user: User,
+    db_session: AsyncSession,
+):
+    recipe = await create_test_recipe(db_session, measurement_tec_user.id)
+    await _make_measurement(client, measurement_tec_user, recipe.id)
+
+    resp = await client.get("/api/measurements/", headers=auth_headers(metrologist_user))
+    item = resp.json()["items"][0]
+    assert item["measured_at"].endswith("+00:00")
+
+    # Same instant written with +02:00 and as UTC: identical results.
+    future_utc = "2099-01-01T08:00:00+00:00"
+    future_rome = "2099-01-01T10:00:00+02:00"
+    past_utc = "2000-01-01T08:00:00+00:00"
+    past_rome = "2000-01-01T10:00:00+02:00"
+    for frm, to in ((past_utc, future_utc), (past_rome, future_rome)):
+        r = await client.get(
+            "/api/measurements/",
+            headers=auth_headers(metrologist_user),
+            params={"date_from": frm, "date_to": to},
+        )
+        assert r.status_code == 200
+        assert r.json()["total"] == 1
+
+    # Boundary: measurement is "now" in UTC; a date_from 1h ahead in UTC,
+    # written as +02:00 (now+3h local wall clock), must exclude it.
+    ahead = (utcnow().replace(microsecond=0)).replace(tzinfo=timezone.utc)
+    from datetime import timedelta
+    ahead_utc = (ahead + timedelta(hours=1)).isoformat()
+    ahead_rome = (ahead + timedelta(hours=1)).astimezone(
+        timezone(timedelta(hours=2))
+    ).isoformat()
+    totals = []
+    for frm in (ahead_utc, ahead_rome):
+        r = await client.get(
+            "/api/measurements/",
+            headers=auth_headers(metrologist_user),
+            params={"date_from": frm},
+        )
+        totals.append(r.json()["total"])
+    assert totals == [0, 0]
+
+
+async def test_report_generated_at_is_local_time(
+    db_session: AsyncSession, metrologist_user: User
+):
+    recipe = await create_test_recipe(db_session, metrologist_user.id)
+    captured: dict[str, str] = {}
+
+    def fake_render(html: str) -> bytes:
+        captured["html"] = html
+        return b"%PDF"
+
+    with patch.object(report_service, "utcnow", return_value=datetime(2026, 10, 6, 8, 0)), \
+            patch.object(report_service, "_render_pdf", side_effect=fake_render):
+        await report_service.generate_measurement_report(db_session, recipe.id)
+
+    assert "Generated 2026-10-06 10:00" in captured["html"]
+
+
+def test_report_filter_day_is_local():
+    """UTC naive 22:00 of Oct 5 is already Oct 6 in Europe/Rome (#42)."""
+    assert report_service._giorno_locale(datetime(2026, 10, 5, 22, 0, 0)) == "2026-10-06"

src/backend/utils/tempo.py

@@ -0,0 +1,34 @@
+"""Time helpers: the DB holds naive UTC, presentation converts to display_timezone (#42)."""
+from datetime import datetime, timezone
+from zoneinfo import ZoneInfo
+
+from src.backend.config import settings
+
+
+def utcnow() -> datetime:
+    """Naive UTC now (the whole DB moves to naive UTC, #42)."""
+    return datetime.now(timezone.utc).replace(tzinfo=None)
+
+
+def as_utc_naive(dt: datetime | None) -> datetime | None:
+    """Aware -> UTC naive; naive is taken as UTC already; None stays None."""
+    if dt is None or dt.tzinfo is None:
+        return dt
+    return dt.astimezone(timezone.utc).replace(tzinfo=None)
+
+
+def to_utc_aware(dt: datetime) -> datetime:
+    """Naive (UTC) or aware datetime -> aware UTC."""
+    if dt.tzinfo is None:
+        return dt.replace(tzinfo=timezone.utc)
+    return dt.astimezone(timezone.utc)
+
+
+def iso_utc(dt: datetime | None) -> str:
+    """ISO 8601 with explicit +00:00; "" for None (CSV cells)."""
+    return to_utc_aware(dt).isoformat() if dt else ""
+
+
+def to_local(dt: datetime) -> datetime:
+    """Naive UTC (or aware) datetime -> aware datetime in settings.display_timezone."""
+    return to_utc_aware(dt).astimezone(ZoneInfo(settings.display_timezone))

src/frontend/flask_app/app.py

@@ -2,7 +2,8 @@
 import json
 import os
 import re
-from datetime import date
+from datetime import date, datetime, timezone
+from zoneinfo import ZoneInfo
 from urllib.parse import urlparse
 
 from flask import Flask, flash, g, jsonify, redirect, url_for, session, request
@@ -154,6 +155,26 @@ def create_app() -> Flask:
         bolded = _BOLD_RX.sub(r"<strong>\1</strong>", escaped)
         return Markup(bolded.replace("\n", "<br>"))
 
+    @app.template_filter("local_dt")
+    def local_dt_filter(value, fmt="%d/%m/%Y %H:%M"):
+        """Show a UTC datetime (ISO string or datetime) in DISPLAY_TIMEZONE.
+
+        A value without timezone is taken as UTC. None or empty gives "-".
+        """
+        if value is None or value == "":
+            return "-"
+        if isinstance(value, str):
+            try:
+                value = datetime.fromisoformat(value.strip().replace("Z", "+00:00"))
+            except ValueError:
+                return value
+        if not isinstance(value, datetime):
+            return str(value)
+        if value.tzinfo is None:
+            value = value.replace(tzinfo=timezone.utc)
+        tz = ZoneInfo(app.config.get("DISPLAY_TIMEZONE") or "Europe/Rome")
+        return value.astimezone(tz).strftime(fmt)
+
     @app.template_filter("tojson_attr")
     def tojson_attr_filter(value):
         """JSON encode safe for HTML attributes (x-data, etc.).

src/frontend/flask_app/blueprints/auth.py

@@ -59,6 +59,45 @@ def _post_login_landing():
     return url_for("auth.profile")
 
 
+def _complete_login(response, fallback_name):
+    """Dopo una risposta di login riuscita: sessione, preferenze, impostazioni (#59).
+
+    Comune al login con password e al login con PIN, cosi' i due restano identici.
+    Ritorna l'utente salvato in sessione.
+    """
+    # Salva in sessione. permanent=True fa valere PERMANENT_SESSION_LIFETIME
+    # (8h, config.py): senza, Flask usa una sessione di durata browser e il
+    # limite configurato non ha mai effetto (#33).
+    session.permanent = True
+    session["api_key"] = response["api_key"]
+    session["user"] = response["user"]
+    session["user_id"] = response["user"]["id"]
+
+    # Applica preferenze utente
+    user = response["user"]
+    if user.get("language_pref"):
+        session["language"] = user["language_pref"]
+    if user.get("theme_pref"):
+        session["theme"] = user["theme_pref"]
+
+    # Carica impostazioni di sistema
+    settings_resp = api_client.get("/api/settings")
+    if not settings_resp.get("error"):
+        logo_path = settings_resp.get("company_logo_path")
+        if logo_path:
+            session["company_logo"] = logo_path
+        auto_logout = settings_resp.get("auto_logout_minutes")
+        if auto_logout:
+            try:
+                session["auto_logout_minutes"] = int(auto_logout)
+            except (ValueError, TypeError):
+                pass
+
+    flash(_("Benvenuto, %(name)s!", name=user.get("display_name", fallback_name)), "success")
+
+    return user
+
+
 @auth_bp.route("/login", methods=["GET", "POST"])
 def login():
     """Login page and form handler."""
@@ -81,35 +120,7 @@ def login():
                 flash(response.get("detail", _("Credenziali non valide")), "error")
                 return render_template("auth/login.html")
 
-            # Salva in sessione. permanent=True fa valere PERMANENT_SESSION_LIFETIME
-            # (8h, config.py): senza, Flask usa una sessione di durata browser e il
-            # limite configurato non ha mai effetto (#33).
-            session.permanent = True
-            session["api_key"] = response["api_key"]
-            session["user"] = response["user"]
-            session["user_id"] = response["user"]["id"]
-
-            # Applica preferenze utente
-            user = response["user"]
-            if user.get("language_pref"):
-                session["language"] = user["language_pref"]
-            if user.get("theme_pref"):
-                session["theme"] = user["theme_pref"]
-
-            # Carica impostazioni di sistema
-            settings_resp = api_client.get("/api/settings")
-            if not settings_resp.get("error"):
-                logo_path = settings_resp.get("company_logo_path")
-                if logo_path:
-                    session["company_logo"] = logo_path
-                auto_logout = settings_resp.get("auto_logout_minutes")
-                if auto_logout:
-                    try:
-                        session["auto_logout_minutes"] = int(auto_logout)
-                    except (ValueError, TypeError):
-                        pass
-
-            flash(_("Benvenuto, %(name)s!", name=user.get("display_name", username)), "success")
+            user = _complete_login(response, username)
 
             # Redirect dopo login (in base al ruolo)
             return redirect(_post_login_landing())
@@ -121,6 +132,55 @@ def login():
     return render_template("auth/login.html")
 
 
+@auth_bp.route("/pin-users", methods=["GET"])
+def pin_users():
+    """Elenco nomi per la vista Operatore del login (#59): solo id e nome.
+
+    Pubblica come il login; se il backend non risponde o non ha il PIN, lista
+    vuota e la pagina apre il form password.
+    """
+    if session.get("api_key"):
+        return jsonify([])
+    try:
+        resp = api_client.get("/api/auth/pin-users")
+    except Exception:
+        return jsonify([])
+    if not isinstance(resp, list):
+        return jsonify([])
+    return jsonify([
+        {"id": u.get("id"), "display_name": u.get("display_name", "")}
+        for u in resp if isinstance(u, dict)
+    ])
+
+
+@auth_bp.route("/login-pin", methods=["POST"])
+def login_pin():
+    """Login con nome + PIN (#59). JSON in/out; CSRF come il login password
+    (header X-CSRFToken, gestito da CSRFProtect)."""
+    data = request.get_json(silent=True) or {}
+    user_id = data.get("user_id")
+    pin = str(data.get("pin", ""))
+    if not isinstance(user_id, int) or not (len(pin) == 4 and pin.isdigit()):
+        return jsonify({"error": True, "status_code": 422, "detail": _("Il PIN deve essere di 4 cifre")}), 422
+
+    try:
+        response = api_client.post("/api/auth/login-pin", data={"user_id": user_id, "pin": pin})
+    except Exception as e:
+        return jsonify({"error": True, "status_code": 502,
+                        "detail": _("Errore di connessione al server: %(error)s", error=str(e))}), 502
+
+    if response.get("error"):
+        status = response.get("status_code") or 401
+        if status == 401:
+            detail = _("PIN errato")
+        else:
+            detail = response.get("detail") or _("Credenziali non valide")
+        return jsonify({"error": True, "status_code": status, "detail": detail}), status
+
+    _complete_login(response, "")  # include il flash di benvenuto
+    return jsonify({"ok": True, "redirect": _post_login_landing()})
+
+
 @auth_bp.route("/logout", methods=["POST"])
 def logout():
     """Clear session and redirect to login."""

src/frontend/flask_app/config.py

@@ -56,6 +56,8 @@ class Config:
     # Babel i18n
     BABEL_DEFAULT_LOCALE = "it"
     BABEL_DEFAULT_TIMEZONE = "Europe/Rome"
+    # Il DB e le API parlano UTC; si converte solo alla presentazione.
+    DISPLAY_TIMEZONE: str = os.getenv("DISPLAY_TIMEZONE", "Europe/Rome")
     LANGUAGES = {"it": "Italiano", "en": "English"}
 
 

src/frontend/flask_app/static/js/csv-export.js

@@ -271,7 +271,7 @@ function csvExport() {
      */
     generateFilename(prefix) {
       const now = new Date();
-      const dateStr = now.toISOString().slice(0, 10); // YYYY-MM-DD
+      const dateStr = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`; // YYYY-MM-DD locale
       const timeStr = now.toTimeString().slice(0, 5).replace(':', ''); // HHMM
 
       return `${prefix}_${dateStr}_${timeStr}.csv`;

src/frontend/flask_app/static/js/pin-pad.js

@@ -0,0 +1,60 @@
+/* Login Operatore: nome + PIN a 4 cifre (#59).
+ * Componente Alpine globale `pinLogin()`, usato da templates/auth/login.html.
+ * Contratto: GET /auth/pin-users -> [{id, display_name}];
+ * POST /auth/login-pin {user_id, pin} -> {ok, redirect} | {error, detail}. */
+function pinLogin() {
+  return {
+    mode: 'pin',        // vista Operatore di default; se l'elenco e' vuoto/fallisce passa a 'password'
+    users: [],
+    selected: null,
+    pin: '',
+    error: '',
+    busy: false,
+
+    init: function () {
+      var self = this;
+      fetch(window.TMF_PIN.usersUrl, { headers: { 'Accept': 'application/json' } })
+        .then(function (r) { return r.ok ? r.json() : []; })
+        .then(function (list) {
+          self.users = Array.isArray(list) ? list : [];
+          if (!self.users.length) self.mode = 'password';  // elenco vuoto: form password
+        })
+        .catch(function () { self.users = []; self.mode = 'password'; });
+    },
+    select: function (u) { this.selected = u; this.pin = ''; this.error = ''; },
+    back: function () { this.selected = null; this.pin = ''; this.error = ''; },
+    del: function () { this.pin = this.pin.slice(0, -1); },
+    press: function (d) {
+      if (this.busy || this.pin.length >= 4) return;
+      this.pin += d;
+      this.error = '';
+      if (this.pin.length === 4) this.submit();  // invio automatico alla quarta cifra
+    },
+    submit: function () {
+      var self = this;
+      var csrf = document.querySelector('meta[name=csrf-token]');
+      self.busy = true;
+      fetch(window.TMF_PIN.loginUrl, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'Accept': 'application/json',
+          'X-CSRFToken': (csrf && csrf.content) || ''
+        },
+        body: JSON.stringify({ user_id: self.selected.id, pin: self.pin })
+      })
+        .then(function (r) { return r.json().catch(function () { return {}; }); })
+        .then(function (d) {
+          if (d.ok && d.redirect) { window.location.href = d.redirect; return; }
+          self.error = d.detail || window.TMF_PIN.msgNet;  // 401 PIN errato, 423 blocco con ora
+          self.pin = '';
+          self.busy = false;
+        })
+        .catch(function () {
+          self.error = window.TMF_PIN.msgNet;
+          self.pin = '';
+          self.busy = false;
+        });
+    }
+  };
+}

src/frontend/flask_app/templates/auth/login.html

@@ -26,8 +26,50 @@
         </p>
       </div>
 
-      <!-- Login Form -->
-      <form method="POST" action="{{ url_for('auth.login') }}" class="space-y-6">
+      <div x-data="pinLogin()" x-init="init()">
+      <!-- Vista Operatore: nome + PIN (#59) -->
+      <div x-show="mode === 'pin'" x-cloak>
+        <!-- Elenco nomi -->
+        <div x-show="!selected">
+          <p class="text-sm text-center text-[var(--text-secondary)] mb-4">{{ _('Chi sei?') }}</p>
+          <div class="grid grid-cols-2 gap-3" id="pin-user-list">
+            <template x-for="u in users" :key="u.id">
+              <button type="button" @click="select(u)"
+                      class="btn btn-secondary min-h-[64px] text-base w-full" x-text="u.display_name"></button>
+            </template>
+          </div>
+        </div>
+        <!-- Tastierino -->
+        <div x-show="selected" id="pin-pad">
+          <p class="text-center font-semibold mb-1" x-text="selected && selected.display_name"></p>
+          <p class="text-sm text-center text-[var(--text-secondary)] mb-3">{{ _('Inserisci il PIN') }}</p>
+          <div class="flex justify-center gap-3 mb-3" aria-hidden="true">
+            <template x-for="i in 4" :key="i">
+              <span class="h-4 w-4 rounded-full border-2 border-[var(--border-color)]"
+                    :class="pin.length >= i ? 'bg-primary-600 border-primary-600' : ''"></span>
+            </template>
+          </div>
+          <p class="text-sm text-center text-red-600 min-h-[1.25rem] mb-2" role="alert" x-text="error"></p>
+          <div class="grid grid-cols-3 gap-3 max-w-xs mx-auto">
+            <template x-for="d in ['1','2','3','4','5','6','7','8','9']" :key="d">
+              <button type="button" @click="press(d)" :disabled="busy"
+                      class="btn btn-secondary h-16 min-w-[64px] text-2xl" x-text="d"></button>
+            </template>
+            <button type="button" @click="back()" :disabled="busy"
+                    class="btn btn-secondary h-16 min-w-[64px] text-sm">{{ _('Indietro') }}</button>
+            <button type="button" @click="press('0')" :disabled="busy"
+                    class="btn btn-secondary h-16 min-w-[64px] text-2xl">0</button>
+            <button type="button" @click="del()" :disabled="busy"
+                    class="btn btn-secondary h-16 min-w-[64px] text-sm">{{ _('Cancella') }}</button>
+          </div>
+        </div>
+        <p class="mt-6 text-center">
+          <a href="#" @click.prevent="mode = 'password'" class="text-sm text-primary-600 hover:underline">{{ _('Accedi con password') }}</a>
+        </p>
+      </div>
+
+      <!-- Login Form (password: admin e chi non ha PIN) -->
+      <form x-show="mode === 'password'" method="POST" action="{{ url_for('auth.login') }}" class="space-y-6">
         <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
         <!-- Username -->
         <div>
@@ -98,6 +140,11 @@
         </div>
       </form>
 
+      <p class="mt-4 text-center" x-show="mode === 'password' && users.length" x-cloak>
+        <a href="#" @click.prevent="mode = 'pin'" class="text-sm text-primary-600 hover:underline">{{ _('Accedi con PIN') }}</a>
+      </p>
+      </div>
+
       <!-- Help Text -->
       <div class="mt-6 text-center">
         <p class="text-xs text-[var(--text-muted)]">
@@ -115,3 +162,15 @@
   </div>
 </div>
 {% endblock %}
+
+{% block extra_js %}
+<script>
+  /* Configurazione e testi per pin-pad.js (#59) */
+  window.TMF_PIN = {
+    usersUrl: {{ url_for('auth.pin_users')|tojson }},
+    loginUrl: {{ url_for('auth.login_pin')|tojson }},
+    msgNet: {{ _('Errore di connessione al server')|tojson }}
+  };
+</script>
+<script src="{{ url_for('static', filename='js/pin-pad.js') }}"></script>
+{% endblock %}

src/frontend/flask_app/templates/measure/task_complete.html

@@ -183,7 +183,7 @@
                     {% for m in measurements|sort(attribute='subtask.marker_number')|sort(attribute='task_info.order_index') %}
                     <tr>
                         <td class="text-center font-mono text-xs" style="color: var(--text-secondary);">
-                            {{ m.measured_at[:16]|replace('T', ' ') if m.measured_at else '-' }}
+                            {{ m.measured_at|local_dt }}
                         </td>
                         <td style="color: var(--text-secondary);" class="text-sm">
                             {{ m.task_info.title if m.task_info else '-' }}

src/frontend/flask_app/templates/statistics/dashboard.html

@@ -312,8 +312,8 @@ function spcDashboard() {
       const params = new URLSearchParams();
       params.set('recipe_id', this.selectedRecipeId);
       if (this.selectedSubtaskId) params.set('subtask_id', this.selectedSubtaskId);
-      if (this.dateFrom) params.set('date_from', this.dateFrom + 'T00:00:00');
-      if (this.dateTo) params.set('date_to', this.dateTo + 'T23:59:59');
+      if (this.dateFrom) params.set('date_from', new Date(this.dateFrom + 'T00:00:00').toISOString());
+      if (this.dateTo) params.set('date_to', new Date(this.dateTo + 'T23:59:59.999').toISOString());
 
       try {
         // Parallel fetch of all endpoints
@@ -417,8 +417,8 @@ function spcDashboard() {
         const params = new URLSearchParams();
         params.set('recipe_id', this.selectedRecipeId);
         if (this.selectedSubtaskId) params.set('subtask_id', this.selectedSubtaskId);
-        if (this.dateFrom) params.set('date_from', this.dateFrom + 'T00:00:00');
-        if (this.dateTo) params.set('date_to', this.dateTo + 'T23:59:59');
+        if (this.dateFrom) params.set('date_from', new Date(this.dateFrom + 'T00:00:00').toISOString());
+        if (this.dateTo) params.set('date_to', new Date(this.dateTo + 'T23:59:59.999').toISOString());
 
         const url = '/statistics/api/report-' + type + '?' + params.toString();
         const resp = await fetch(url);

src/frontend/flask_app/tests/test_auth.py

@@ -136,3 +136,67 @@ class TestLanguageSwitch:
         with client.session_transaction() as sess:
             # Invalid language should NOT be stored
             assert sess.get("language") != "xx"
+
+
+class TestPinLogin:
+    """Login Operatore con nome + PIN (#59)."""
+
+    USER = {
+        "id": 7, "username": "mario", "display_name": "Mario Rossi",
+        "roles": ["MeasurementTec"], "is_admin": False,
+        "language_pref": "it", "theme_pref": "light", "active": True,
+    }
+
+    def test_login_page_has_pin_view_and_password_link(self, client):
+        resp = client.get("/auth/login")
+        assert b"pin-pad.js" in resp.data
+        assert b"pin-pad" in resp.data  # tastierino presente nel markup
+        assert b'name="password"' in resp.data  # form password ancora presente
+
+    def test_pin_users_listed(self, client, mock_api_client):
+        mock_api_client.get.return_value = [
+            {"id": 7, "display_name": "Mario Rossi", "secret": "x"},
+        ]
+        resp = client.get("/auth/pin-users")
+        assert resp.status_code == 200
+        assert resp.get_json() == [{"id": 7, "display_name": "Mario Rossi"}]
+
+    def test_pin_users_empty_on_error(self, client, mock_api_client):
+        mock_api_client.get.return_value = {"error": True, "detail": "boom"}
+        assert client.get("/auth/pin-users").get_json() == []
+
+    def test_pin_users_empty_list_falls_back(self, client, mock_api_client):
+        mock_api_client.get.return_value = []
+        assert client.get("/auth/pin-users").get_json() == []
+
+    def test_login_pin_success_sets_session(self, client, mock_api_client):
+        mock_api_client.post.return_value = {"api_key": "pin-key", "user": self.USER}
+        mock_api_client.get.return_value = {}
+        resp = client.post("/auth/login-pin", json={"user_id": 7, "pin": "1234"})
+        assert resp.status_code == 200
+        assert resp.get_json()["ok"] is True
+        assert resp.get_json()["redirect"]
+        mock_api_client.post.assert_called_once_with(
+            "/api/auth/login-pin", data={"user_id": 7, "pin": "1234"})
+        with client.session_transaction() as sess:
+            assert sess["api_key"] == "pin-key"
+            assert sess["user_id"] == 7
+            assert sess.permanent is True
+
+    def test_login_pin_wrong_pin_401(self, client, mock_api_client):
+        mock_api_client.post.return_value = {"error": True, "status_code": 401, "detail": "x"}
+        resp = client.post("/auth/login-pin", json={"user_id": 7, "pin": "0000"})
+        assert resp.status_code == 401
+        assert resp.get_json()["detail"] == "PIN errato"
+
+    def test_login_pin_locked_423_shows_detail(self, client, mock_api_client):
+        mock_api_client.post.return_value = {
+            "error": True, "status_code": 423, "detail": "Utente bloccato fino alle 10:15"}
+        resp = client.post("/auth/login-pin", json={"user_id": 7, "pin": "0000"})
+        assert resp.status_code == 423
+        assert "10:15" in resp.get_json()["detail"]
+
+    def test_login_pin_invalid_pin_422(self, client, mock_api_client):
+        resp = client.post("/auth/login-pin", json={"user_id": 7, "pin": "12"})
+        assert resp.status_code == 422
+        mock_api_client.post.assert_not_called()

src/frontend/flask_app/tests/test_local_dt.py

@@ -0,0 +1,31 @@
+"""Filtro local_dt: il backend parla UTC, la presentazione e' in Europe/Rome (#42)."""
+from datetime import datetime, timezone
+
+import pytest
+
+
+@pytest.fixture
+def local_dt(flask_app):
+    return flask_app.jinja_env.filters["local_dt"]
+
+
+def test_summer_time(local_dt):
+    assert local_dt("2026-10-06T08:00:00+00:00") == "06/10/2026 10:00"
+
+
+def test_winter_time(local_dt):
+    assert local_dt("2026-01-15T08:00:00+00:00") == "15/01/2026 09:00"
+
+
+def test_naive_is_utc(local_dt):
+    assert local_dt("2026-10-06T08:00:00") == "06/10/2026 10:00"
+
+
+def test_datetime_object_and_format(local_dt):
+    dt = datetime(2026, 10, 6, 8, 0, tzinfo=timezone.utc)
+    assert local_dt(dt, "%H:%M") == "10:00"
+
+
+@pytest.mark.parametrize("empty", [None, ""])
+def test_empty(local_dt, empty):
+    assert local_dt(empty) == "-"

src/frontend/flask_app/tests/test_measure.py

@@ -407,6 +407,21 @@ class TestTaskComplete:
         assert resp.status_code == 200
         assert b"productionClock(" in resp.data
 
+    def test_measured_at_shown_in_local_time(self, logged_in_client, mock_api_client):
+        """#42: the API sends UTC; the summary shows Europe/Rome."""
+        mock_api_client.get.side_effect = [
+            {"id": 1, "code": "REC-001", "name": "Test Recipe", "version": 1},
+            [{"id": 1, "title": "Task 1", "order_index": 0, "subtasks": [
+                {"id": 1, "marker_number": 1, "description": "d", "nominal": 1.0,
+                 "unit": "mm"}]}],
+            None,
+            {"items": [{"id": 1, "subtask_id": 1, "value": 1.0, "pass_fail": "pass",
+                        "measured_at": "2026-10-06T08:00:00+00:00"}]},
+        ]
+        resp = logged_in_client.get("/measure/complete/1?version_id=5")
+        assert resp.status_code == 200
+        assert "06/10/2026 10:00" in resp.get_data(as_text=True)
+
     def test_measurements_filtered_by_lot_serial_and_operator(
         self, logged_in_client, mock_api_client,
     ):