diff --git a/tests/services/test_cache.py b/tests/services/test_cache.py
new file mode 100644
index 0000000..37f0636
--- /dev/null
+++ b/tests/services/test_cache.py
@@ -0,0 +1,122 @@
+import asyncio
+import json
+
+from valkey.exceptions import ValkeyError
+
+from app.core.config import Settings
+from app.services.cache import CacheClient
+
+
+def make_settings(**overrides):
+    return Settings(datamall_api_key="test-account-key", **overrides)
+
+
+def run(coro):
+    return asyncio.run(coro)
+
+
+class FakeValkeyClient:
+    def __init__(self, get_value=None, get_error=None, set_error=None):
+        self.get_value = get_value
+        self.get_error = get_error
+        self.set_error = set_error
+        self.get_calls = []
+        self.set_calls = []
+        self.ping_calls = 0
+        self.closed = False
+
+    async def ping(self):
+        self.ping_calls += 1
+
+    async def get(self, key):
+        self.get_calls.append(key)
+        if self.get_error is not None:
+            raise self.get_error
+        return self.get_value
+
+    async def set(self, key, value, ex=None):
+        self.set_calls.append((key, value, ex))
+        if self.set_error is not None:
+            raise self.set_error
+
+    async def aclose(self):
+        self.closed = True
+
+
+def test_build_cache_key_is_deterministic():
+    first = CacheClient.build_cache_key("/v3/BusArrival", {"BusStopCode": "12345", "ServiceNo": "10"})
+    second = CacheClient.build_cache_key("/v3/BusArrival", {"ServiceNo": "10", "BusStopCode": "12345"})
+
+    assert first == second
+
+
+def test_get_json_returns_parsed_payload():
+    cache = CacheClient(make_settings(valkey_enabled=True))
+    cache._client = FakeValkeyClient(get_value=json.dumps({"value": [1, 2, 3]}))
+
+    result = run(cache.get_json("lta:/v3/BusArrival:test"))
+
+    assert result == {"value": [1, 2, 3]}
+
+
+def test_get_json_returns_none_for_invalid_payload():
+    cache = CacheClient(make_settings(valkey_enabled=True))
+    cache._client = FakeValkeyClient(get_value="not-json")
+
+    result = run(cache.get_json("lta:/v3/BusArrival:test"))
+
+    assert result is None
+
+
+def test_get_json_returns_none_when_cache_is_unavailable():
+    cache = CacheClient(make_settings(valkey_enabled=True))
+    cache._client = FakeValkeyClient(get_error=ValkeyError("boom"))
+
+    result = run(cache.get_json("lta:/v3/BusArrival:test"))
+
+    assert result is None
+
+
+def test_set_json_uses_default_ttl_when_not_provided():
+    cache = CacheClient(make_settings(valkey_default_ttl_seconds=321))
+    cache._client = FakeValkeyClient()
+
+    run(cache.set_json("lta:/v3/BusArrival:test", {"value": True}))
+
+    assert cache._client.set_calls == [("lta:/v3/BusArrival:test", '{"value":true}', 321)]
+
+
+def test_set_json_uses_explicit_ttl():
+    cache = CacheClient(make_settings(valkey_default_ttl_seconds=321))
+    cache._client = FakeValkeyClient()
+
+    run(cache.set_json("lta:/v3/BusArrival:test", {"value": True}, ttl_seconds=12))
+
+    assert cache._client.set_calls == [("lta:/v3/BusArrival:test", '{"value":true}', 12)]
+
+
+def test_startup_disables_cache_when_ping_fails(monkeypatch):
+    fake_client = FakeValkeyClient()
+
+    class FakeFactory:
+        def __init__(self):
+            self.calls = []
+
+        def __call__(self, url, decode_responses, socket_connect_timeout):
+            self.calls.append((url, decode_responses, socket_connect_timeout))
+            return fake_client
+
+    factory = FakeFactory()
+
+    async def failing_ping():
+        raise ValkeyError("boom")
+
+    fake_client.ping = failing_ping
+    monkeypatch.setattr("app.services.cache.valkey.from_url", factory)
+
+    cache = CacheClient(make_settings(valkey_enabled=True))
+    run(cache.startup())
+
+    assert factory.calls == [("redis://valkey:6379/0", True, 1.0)]
+    assert fake_client.closed is True
+    assert cache._client is None
\ No newline at end of file
diff --git a/tests/services/test_lta_client.py b/tests/services/test_lta_client.py
new file mode 100644
index 0000000..98a6bfc
--- /dev/null
+++ b/tests/services/test_lta_client.py
@@ -0,0 +1,104 @@
+import asyncio
+
+import httpx
+
+from app.core.config import Settings
+from app.services import lta_client as lta_client_module
+from app.services.lta_client import LTAClient
+
+
+def make_settings(**overrides):
+    return Settings(datamall_api_key="test-account-key", **overrides)
+
+
+def run(coro):
+    return asyncio.run(coro)
+
+
+class FakeResponse:
+    def __init__(self, payload=None, status_code=200):
+        self._payload = payload if payload is not None else {"value": []}
+        self.status_code = status_code
+
+    def raise_for_status(self):
+        if self.status_code >= 400:
+            request = httpx.Request("GET", "https://example.test")
+            response = httpx.Response(self.status_code, request=request)
+            raise httpx.HTTPStatusError("boom", request=request, response=response)
+
+    def json(self):
+        return self._payload
+
+
+class FakeAsyncClient:
+    instances = []
+
+    def __init__(self, **kwargs):
+        self.kwargs = kwargs
+        self.calls = []
+        self.closed = False
+        FakeAsyncClient.instances.append(self)
+
+    async def get(self, path, params=None):
+        self.calls.append((path, params))
+        return FakeResponse({"path": path, "params": params})
+
+    async def aclose(self):
+        self.closed = True
+
+
+def test_startup_configures_httpx_client(monkeypatch):
+    FakeAsyncClient.instances = []
+    monkeypatch.setattr(lta_client_module.httpx, "AsyncClient", FakeAsyncClient)
+
+    client = LTAClient(make_settings(request_timeout_seconds=7.5, max_connections=12, max_keepalive_connections=6))
+    run(client.startup())
+
+    created = FakeAsyncClient.instances[0]
+    assert created.kwargs["base_url"] == "https://datamall2.mytransport.sg/ltaodataservice"
+    assert created.kwargs["headers"] == {"AccountKey": "test-account-key", "accept": "application/json"}
+    assert created.kwargs["timeout"].connect == 7.5
+    assert created.kwargs["timeout"].read == 7.5
+    assert created.kwargs["timeout"].write == 7.5
+    assert created.kwargs["timeout"].pool == 7.5
+    assert created.kwargs["limits"].max_connections == 12
+    assert created.kwargs["limits"].max_keepalive_connections == 6
+
+
+def test_get_raises_before_startup():
+    client = LTAClient(make_settings())
+
+    try:
+        run(client.get("/v3/BusArrival"))
+        raised = False
+    except RuntimeError as err:
+        raised = True
+        assert str(err) == "LTA client not initialized"
+
+    assert raised is True
+
+
+def test_get_returns_json_payload(monkeypatch):
+    FakeAsyncClient.instances = []
+    monkeypatch.setattr(lta_client_module.httpx, "AsyncClient", FakeAsyncClient)
+
+    client = LTAClient(make_settings())
+    run(client.startup())
+
+    payload = run(client.get("/v3/BusArrival", params={"BusStopCode": "12345"}))
+
+    assert payload == {"path": "/v3/BusArrival", "params": {"BusStopCode": "12345"}}
+    assert FakeAsyncClient.instances[0].calls == [("/v3/BusArrival", {"BusStopCode": "12345"})]
+
+
+def test_shutdown_closes_client(monkeypatch):
+    FakeAsyncClient.instances = []
+    monkeypatch.setattr(lta_client_module.httpx, "AsyncClient", FakeAsyncClient)
+
+    client = LTAClient(make_settings())
+    run(client.startup())
+    created = FakeAsyncClient.instances[0]
+
+    run(client.shutdown())
+
+    assert created.closed is True
\ No newline at end of file