diff --git a/tests/build_scripts/test_location_message_policy_integration.py b/tests/build_scripts/test_location_message_policy_integration.py
index 9ea76045..63cc42a3 100644
--- a/tests/build_scripts/test_location_message_policy_integration.py
+++ b/tests/build_scripts/test_location_message_policy_integration.py
@@ -5,6 +5,20 @@ CPP = ROOT / "lib/tdeck_ui/UI/LXMF/UIManager.cpp"
 HEADER = ROOT / "lib/tdeck_ui/UI/LXMF/UIManager.h"
 
 
+def guarded_block(source: str, condition: str) -> tuple[int, int]:
+    condition_start = source.index(condition)
+    open_brace = source.index("{", condition_start)
+    depth = 0
+    for index in range(open_brace, len(source)):
+        if source[index] == "{":
+            depth += 1
+        elif source[index] == "}":
+            depth -= 1
+            if depth == 0:
+                return open_brace, index
+    raise AssertionError("unterminated guarded block")
+
+
 def test_inbound_location_policy_precedes_chat_persistence():
     source = CPP.read_text()
     handler = source[source.index("void UIManager::on_message_received") :]
@@ -19,6 +33,19 @@ def test_inbound_location_policy_precedes_chat_persistence():
     assert "message.source_hash()" in handler[:save]
     assert "location_decision.authenticated_sender" in handler[:save]
 
+    guard_start, guard_end = guarded_block(
+        handler,
+        "if (message.signature_validated() &&\n"
+        "        source_hash.size() == Telemetry::PEER_ID_SIZE)",
+    )
+    guarded = handler[guard_start:guard_end]
+    assert "RNS::Utilities::OS::ltime()" in guarded
+    assert "classifyInboundLocationMessage" in guarded
+    assert "_peer_locations.apply" in guarded
+    assert "location_decision.authenticated_sender" in guarded
+    assert handler.count("classifyInboundLocationMessage") == 1
+    assert handler.count("_peer_locations.apply") == 1
+
 
 def test_peer_location_store_is_durable_ui_manager_state():
     header = HEADER.read_text()
diff --git a/tests/build_scripts/test_tdeck_environment_isolation.py b/tests/build_scripts/test_tdeck_environment_isolation.py
index d2753ea5..ea11ab2d 100644
--- a/tests/build_scripts/test_tdeck_environment_isolation.py
+++ b/tests/build_scripts/test_tdeck_environment_isolation.py
@@ -2,6 +2,9 @@ from pathlib import Path
 
 ROOT = Path(__file__).resolve().parents[2]
 CONFIG = ROOT / "platformio.ini"
+MAIN = ROOT / "src/main.cpp"
+HARDWARE_RUNNER = ROOT / "tests/hardware/run_e2e.sh"
+VOICE_README = ROOT / "tools/voice_test/README.md"
 
 
 def section(text: str, name: str) -> str:
@@ -19,5 +22,18 @@ def test_test_hooks_are_isolated_from_production_tdeck():
     assert "PYXIS_TEST_TCP_PORT" not in production
     assert "extends = env:tdeck" in instrumented
     assert "-DPYXIS_TEST_HOOKS" in instrumented
-    assert "PYXIS_TEST_TCP_HOST" in instrumented
-    assert "PYXIS_TEST_TCP_PORT" in instrumented
+    assert '\'-DPYXIS_TEST_TCP_HOST="${sysenv.PYXIS_TEST_TCP_HOST}"\'' in instrumented
+    assert '\'-DPYXIS_TEST_TCP_PORT="${sysenv.PYXIS_TEST_TCP_PORT}"\'' in instrumented
+
+
+def test_test_hook_defaults_and_harness_target_are_safe():
+    main = MAIN.read_text()
+    hook_defaults = main[main.index("#ifdef PYXIS_TEST_HOOKS") : main.index("#include <Wire.h>")]
+    assert '#define PYXIS_TEST_TCP_HOST ""' in hook_defaults
+    assert '#define PYXIS_TEST_TCP_PORT ""' in hook_defaults
+
+    runner = HARDWARE_RUNNER.read_text()
+    assert 'PYXIS_ENV="${PYXIS_ENV:-tdeck-test}"' in runner
+
+    voice_readme = VOICE_README.read_text()
+    assert "pio run -e tdeck-test" in voice_readme