@@ -14,26 +14,77 @@
 user configured for NZ dollars/cents saw "p/kWh" (pence) in the chart legend regardless.
 """
 
+import re
+
+from web import WebInterface
+
+
+def _make_web(my_predbat):
+    """
+    Build a minimal WebInterface bound to my_predbat, bypassing ComponentBase.__init__ (which
+    would stand up the real aiohttp app). currency_symbols/now_utc/minutes_now/etc are all
+    read-only properties on ComponentBase that delegate to self.base, so nothing else needs
+    setting here for get_chart() to run.
+    """
+    w = WebInterface.__new__(WebInterface)
+    w.base = my_predbat
+    w.log = my_predbat.log
+    w.prefix = my_predbat.prefix
+    return w
+
 
 def test_rates_chart_series_names_use_currency_symbol(my_predbat):
     """
-    Directly mirrors the series-name formatting used in WebInterface.get_chart's "Rates"
-    branch (web.py) - get_chart itself requires a fully computed plan (soc_kw_best populated)
-    before it reaches this branch, so this tests the formatting logic directly rather than
-    standing up that heavier machinery.
+    Calls the real WebInterface.get_chart("Rates") and checks the rendered series names,
+    rather than re-testing the formatting logic in isolation - a prior version of this test
+    only duplicated the format string inline, so it would still pass even if web.py regressed
+    back to a hardcoded "p/kWh" (Copilot review on PR #4288).
+
+    get_chart() gates on soc_kw_best being populated (dashboard_values) and reads the Hourly/
+    Today series from get_history_wrapper() - both are stubbed directly rather than trying to
+    reproduce realistic HA history formatting, since only the currency-dependent series *names*
+    are under test here, not the underlying rate data.
     """
     print("**** test_rates_chart_series_names_use_currency_symbol ****")
 
-    for currency_symbols, expected_minor in [("£p", "p"), ("$c", "c"), ("€c", "c")]:
-        my_predbat.currency_symbols = currency_symbols
-        hourly_name = "Hourly {}/kWh".format(my_predbat.currency_symbols[1])
-        today_name = "Today {}/kWh".format(my_predbat.currency_symbols[1])
+    original_currency_symbols = my_predbat.currency_symbols
+    original_dashboard_values = getattr(my_predbat, "dashboard_values", None)
+
+    try:
+        w = _make_web(my_predbat)
+        my_predbat.dashboard_values = {
+            "predbat.soc_kw_best": {"attributes": {"results": {"2026-01-01T00:00:00+00:00": 5.0}}},
+            "predbat.rates": {"attributes": {"results": {"2026-01-01T00:00:00+00:00": 10.0}}},
+        }
+        fake_history = [
+            [
+                {"state": 10.5, "last_updated": "2026-01-01T00:00:00+00:00"},
+                {"state": 12.3, "last_updated": "2026-01-01T00:30:00+00:00"},
+            ]
+        ]
+        w.get_history_wrapper = lambda *a, **kw: fake_history
+
+        for currency_symbols, expected_minor in [("£p", "p"), ("$c", "c"), ("€c", "c")]:
+            my_predbat.currency_symbols = currency_symbols
+
+            result = w.get_chart("Rates")
+            series_names = re.findall(r"name: '([^']*)'", result)
+
+            expected_hourly = "Hourly {}/kWh".format(expected_minor)
+            expected_today = "Today {}/kWh".format(expected_minor)
 
-        assert hourly_name == "Hourly {}/kWh".format(expected_minor), f"Expected 'Hourly {expected_minor}/kWh', got '{hourly_name}'"
-        assert today_name == "Today {}/kWh".format(expected_minor), f"Expected 'Today {expected_minor}/kWh', got '{today_name}'"
-        if expected_minor != "p":
-            assert "p/kWh" not in hourly_name and "p/kWh" not in today_name, f"Series name should not be hardcoded to pence for currency_symbols={currency_symbols}"
+            assert expected_hourly in series_names, f"Expected series '{expected_hourly}' in {series_names} for currency_symbols={currency_symbols}"
+            assert expected_today in series_names, f"Expected series '{expected_today}' in {series_names} for currency_symbols={currency_symbols}"
+            if expected_minor != "p":
+                assert not any("p/kWh" in name for name in series_names), f"Series names should not be hardcoded to pence for currency_symbols={currency_symbols}, got {series_names}"
 
-    print("✓ Rates chart series names correctly follow currency_symbols[1] (£p, $c, €c all verified)")
-    print("✓ Test passed")
-    return False
+        print("✓ Rates chart series names correctly follow currency_symbols[1] (£p, $c, €c all verified against the real get_chart() output)")
+        print("✓ Test passed")
+        return False
+    finally:
+        my_predbat.currency_symbols = original_currency_symbols
+        if original_dashboard_values is None:
+            if hasattr(my_predbat, "dashboard_values"):
+                del my_predbat.dashboard_values
+        else:
+            my_predbat.dashboard_values = original_dashboard_values