diff --git a/testing/backend/unit/test_cache_module.py b/testing/backend/unit/test_cache_module.py
new file mode 100644
index 00000000..d093f85c
--- /dev/null
+++ b/testing/backend/unit/test_cache_module.py
@@ -0,0 +1,136 @@
+"""
+Unit tests for cache module-level functions in backend/secuscan/cache.py.
+
+Covers:
+- init_cache: initialises the global cache instance
+- get_cache: returns the global cache instance
+- invalidate_view_cache: clears caches with view-related prefixes
+- invalidate_plugin_caches: clears caches with plugin-related prefixes
+
+CacheClient itself is already tested in test_cache_helpers.py.
+This file tests ONLY the module-level functions.
+"""
+
+import asyncio
+import pytest
+
+from backend.secuscan.cache import (
+    get_cache,
+    init_cache,
+    invalidate_plugin_caches,
+    invalidate_view_cache,
+)
+
+
+def _run(coro):
+    return asyncio.run(coro)
+
+
+# ---------------------------------------------------------------------------
+# init_cache
+# ---------------------------------------------------------------------------
+
+
+class TestInitCache:
+    def test_returns_cache_client(self):
+        cache = _run(init_cache())
+        from backend.secuscan.cache import CacheClient
+        assert isinstance(cache, CacheClient)
+
+    def test_sets_global_cache(self):
+        _run(init_cache())
+        cache = _run(get_cache())
+        assert cache is not None
+
+    def test_replaces_existing_global_instance(self):
+        first = _run(init_cache())
+        second = _run(init_cache())
+        from backend.secuscan.cache import CacheClient
+        assert isinstance(first, CacheClient)
+        assert isinstance(second, CacheClient)
+        # init_cache replaces the global each time
+        assert first is not second
+
+
+# ---------------------------------------------------------------------------
+# get_cache
+# ---------------------------------------------------------------------------
+
+
+class TestGetCache:
+    def test_returns_initialised_cache(self):
+        _run(init_cache())
+        cache = _run(get_cache())
+        from backend.secuscan.cache import CacheClient
+        assert isinstance(cache, CacheClient)
+
+    def test_raises_when_not_initialised(self):
+        import backend.secuscan.cache as cache_module
+        cache_module.cache = None
+        try:
+            with pytest.raises(RuntimeError, match="not initialized"):
+                _run(get_cache())
+        finally:
+            cache_module.cache = None
+
+
+# ---------------------------------------------------------------------------
+# invalidate_view_cache
+# ---------------------------------------------------------------------------
+
+
+class TestInvalidateViewCache:
+    def test_noop_when_cache_not_initialised(self):
+        import backend.secuscan.cache as cache_module
+        cache_module.cache = None
+        # Should not raise
+        _run(invalidate_view_cache())
+
+    def test_deletes_view_prefixes(self):
+        import backend.secuscan.cache as cache_module
+        cache = _run(init_cache())
+        deleted_prefixes = []
+        original_delete_prefix = cache.delete_prefix
+
+        async def tracking_delete_prefix(prefix: str):
+            deleted_prefixes.append(prefix)
+            return await original_delete_prefix(prefix)
+
+        cache.delete_prefix = tracking_delete_prefix
+        cache_module.cache = cache
+
+        _run(invalidate_view_cache())
+
+        expected = ["summary:", "findings:", "reports:", "tasks:"]
+        assert sorted(deleted_prefixes) == sorted(expected)
+
+
+# ---------------------------------------------------------------------------
+# invalidate_plugin_caches
+# ---------------------------------------------------------------------------
+
+
+class TestInvalidatePluginCaches:
+    def test_noop_when_cache_not_initialised(self):
+        import backend.secuscan.cache as cache_module
+        cache_module.cache = None
+        # Should not raise
+        _run(invalidate_plugin_caches())
+
+    def test_deletes_plugin_prefixes(self):
+        import backend.secuscan.cache as cache_module
+        cache = _run(init_cache())
+        deleted_prefixes = []
+        original_delete_prefix = cache.delete_prefix
+
+        async def tracking_delete_prefix(prefix: str):
+            deleted_prefixes.append(prefix)
+            return await original_delete_prefix(prefix)
+
+        cache.delete_prefix = tracking_delete_prefix
+        cache_module.cache = cache
+
+        _run(invalidate_plugin_caches())
+
+        expected = ["summary:", "plugins:"]
+        assert sorted(deleted_prefixes) == sorted(expected)
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