refactor: extract httpx mock helpers in price history tests

- create_mock_httpx_client() for mocking AsyncClient with various configs
- create_bitfinex_ticker_response() for creating ticker response arrays

Reduces test boilerplate significantly.

backend/tests/test_price_history.py

@@ -2,6 +2,7 @@
 
 from contextlib import asynccontextmanager
 from datetime import UTC, datetime
+from typing import Any
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
@@ -11,14 +12,53 @@ from price_fetcher import PAIR_BTC_EUR, SOURCE_BITFINEX, fetch_btc_eur_price
 from worker import process_bitcoin_price_job
 
 
+def create_mock_httpx_client(
+    json_response: list[Any] | dict[str, Any] | None = None,
+    raise_for_status_error: Exception | None = None,
+    get_error: Exception | None = None,
+) -> AsyncMock:
+    """
+    Create a mock httpx.AsyncClient for testing.
+
+    Args:
+        json_response: The JSON data to return from response.json()
+        raise_for_status_error: Exception to raise from response.raise_for_status()
+        get_error: Exception to raise from client.get()
+
+    Returns:
+        A mock AsyncClient configured as an async context manager.
+    """
+    mock_client = AsyncMock()
+    mock_client.__aenter__.return_value = mock_client
+    mock_client.__aexit__.return_value = None
+
+    if get_error:
+        mock_client.get.side_effect = get_error
+    else:
+        mock_response = MagicMock()
+        if raise_for_status_error:
+            mock_response.raise_for_status.side_effect = raise_for_status_error
+        else:
+            mock_response.raise_for_status = MagicMock()
+        mock_response.json.return_value = json_response
+        mock_client.get.return_value = mock_response
+
+    return mock_client
+
+
+def create_bitfinex_ticker_response(price: float) -> list[float]:
+    """Create a Bitfinex ticker response array with the given price at index 6."""
+    return [0, 0, 0, 0, 0, 0, price, 0, 0, 0]
+
+
 class TestFetchBtcEurPrice:
     """Tests for the Bitfinex price fetcher."""
 
     @pytest.mark.asyncio
     async def test_parses_response_correctly(self):
         """Verify price is extracted from correct index in response array."""
-        mock_response = MagicMock()
+        # Full Bitfinex ticker format for documentation
-        mock_response.json.return_value = [
+        json_response = [
             100.0,  # BID
             10.0,  # BID_SIZE
             101.0,  # ASK
@@ -30,12 +70,7 @@ class TestFetchBtcEurPrice:
             96000.0,  # HIGH
             94000.0,  # LOW
         ]
-        mock_response.raise_for_status = MagicMock()
+        mock_client = create_mock_httpx_client(json_response=json_response)
-
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with patch("price_fetcher.httpx.AsyncClient", return_value=mock_client):
             price, timestamp = await fetch_btc_eur_price()
@@ -49,15 +84,10 @@ class TestFetchBtcEurPrice:
         """Verify HTTP errors are propagated."""
         import httpx
 
-        mock_response = MagicMock()
+        error = httpx.HTTPStatusError(
-        mock_response.raise_for_status.side_effect = httpx.HTTPStatusError(
             "Server Error", request=MagicMock(), response=MagicMock()
         )
-
+        mock_client = create_mock_httpx_client(raise_for_status_error=error)
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with (
             patch("price_fetcher.httpx.AsyncClient", return_value=mock_client),
@@ -70,10 +100,8 @@ class TestFetchBtcEurPrice:
         """Verify network errors (ConnectError, TimeoutException) are propagated."""
         import httpx
 
-        mock_client = AsyncMock()
+        error = httpx.ConnectError("Connection refused")
-        mock_client.get.side_effect = httpx.ConnectError("Connection refused")
+        mock_client = create_mock_httpx_client(get_error=error)
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with (
             patch("price_fetcher.httpx.AsyncClient", return_value=mock_client),
@@ -84,14 +112,7 @@ class TestFetchBtcEurPrice:
     @pytest.mark.asyncio
     async def test_raises_on_invalid_response_format(self):
         """Verify ValueError is raised for unexpected response format."""
-        mock_response = MagicMock()
+        mock_client = create_mock_httpx_client(json_response={"error": "unexpected"})
-        mock_response.json.return_value = {"error": "unexpected"}
-        mock_response.raise_for_status = MagicMock()
-
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with (
             patch("price_fetcher.httpx.AsyncClient", return_value=mock_client),
@@ -102,14 +123,7 @@ class TestFetchBtcEurPrice:
     @pytest.mark.asyncio
     async def test_raises_on_short_array(self):
         """Verify ValueError is raised if array is too short."""
-        mock_response = MagicMock()
+        mock_client = create_mock_httpx_client(json_response=[1, 2, 3])  # Too short
-        mock_response.json.return_value = [1, 2, 3]  # Too short
-        mock_response.raise_for_status = MagicMock()
-
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with (
             patch("price_fetcher.httpx.AsyncClient", return_value=mock_client),
@@ -210,14 +224,9 @@ class TestManualFetch:
     @pytest.mark.asyncio
     async def test_creates_record_on_success(self, client_factory, admin_user):
         """Verify manual fetch creates a price history record."""
-        mock_response = MagicMock()
+        mock_client = create_mock_httpx_client(
-        mock_response.json.return_value = [0, 0, 0, 0, 0, 0, 95123.45, 0, 0, 0]
+            json_response=create_bitfinex_ticker_response(95123.45)
-        mock_response.raise_for_status = MagicMock()
+        )
-
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with patch("price_fetcher.httpx.AsyncClient", return_value=mock_client):
             async with client_factory.create(cookies=admin_user["cookies"]) as authed:
@@ -235,14 +244,9 @@ class TestManualFetch:
     @pytest.mark.asyncio
     async def test_record_persisted_to_database(self, client_factory, admin_user):
         """Verify the created record can be retrieved."""
-        mock_response = MagicMock()
+        mock_client = create_mock_httpx_client(
-        mock_response.json.return_value = [0, 0, 0, 0, 0, 0, 87654.32, 0, 0, 0]
+            json_response=create_bitfinex_ticker_response(87654.32)
-        mock_response.raise_for_status = MagicMock()
+        )
-
-        mock_client = AsyncMock()
-        mock_client.get.return_value = mock_response
-        mock_client.__aenter__.return_value = mock_client
-        mock_client.__aexit__.return_value = None
 
         with patch("price_fetcher.httpx.AsyncClient", return_value=mock_client):
             async with client_factory.create(cookies=admin_user["cookies"]) as authed:
@@ -309,14 +313,9 @@ class TestProcessBitcoinPriceJob:
     @pytest.mark.asyncio
     async def test_stores_price_on_success(self):
         """Verify price is stored in database on successful fetch."""
-        mock_response = MagicMock()
+        mock_http_client = create_mock_httpx_client(
-        mock_response.json.return_value = [0, 0, 0, 0, 0, 0, 95000.0, 0, 0, 0]
+            json_response=create_bitfinex_ticker_response(95000.0)
-        mock_response.raise_for_status = MagicMock()
+        )
-
-        mock_http_client = AsyncMock()
-        mock_http_client.get.return_value = mock_response
-        mock_http_client.__aenter__.return_value = mock_http_client
-        mock_http_client.__aexit__.return_value = None
 
         mock_conn = AsyncMock()
         mock_pool = create_mock_pool(mock_conn)
@@ -338,15 +337,10 @@ class TestProcessBitcoinPriceJob:
         """Verify no exception is raised and no DB insert on API error."""
         import httpx
 
-        mock_response = MagicMock()
+        error = httpx.HTTPStatusError(
-        mock_response.raise_for_status.side_effect = httpx.HTTPStatusError(
             "Server Error", request=MagicMock(), response=MagicMock()
         )
-
+        mock_http_client = create_mock_httpx_client(raise_for_status_error=error)
-        mock_http_client = AsyncMock()
-        mock_http_client.get.return_value = mock_response
-        mock_http_client.__aenter__.return_value = mock_http_client
-        mock_http_client.__aexit__.return_value = None
 
         mock_conn = AsyncMock()
         mock_pool = create_mock_pool(mock_conn)
@@ -361,14 +355,9 @@ class TestProcessBitcoinPriceJob:
     @pytest.mark.asyncio
     async def test_fails_silently_on_db_error(self):
         """Verify no exception is raised on database error."""
-        mock_response = MagicMock()
+        mock_http_client = create_mock_httpx_client(
-        mock_response.json.return_value = [0, 0, 0, 0, 0, 0, 95000.0, 0, 0, 0]
+            json_response=create_bitfinex_ticker_response(95000.0)
-        mock_response.raise_for_status = MagicMock()
+        )
-
-        mock_http_client = AsyncMock()
-        mock_http_client.get.return_value = mock_response
-        mock_http_client.__aenter__.return_value = mock_http_client
-        mock_http_client.__aexit__.return_value = None
 
         mock_conn = AsyncMock()
         mock_conn.execute.side_effect = Exception("Database connection error")