feat(diagnostics): capture /oic/res discovery links

/oic/res is OCF's baseline resource-discovery endpoint: a unicast
RETRIEVE returns every href/Collection the connection hosts, not just
the one /device/0 seed path the coordinator polls. Relevant to the OCF
"Composite Device" model (issue #177) -- a single physical unit sharing
one IP/session across more than one logical Device, each exposed as its
own Collection resource (same rt shape as our own /device/0). Nothing
routes on this yet; captured alongside the existing /oic/p and /oic/d
reads so a report from a multi-unit device shows us whether its
firmware actually implements that model before any code assumes it does.

tests/localthings/test_diagnostics.py

@@ -80,6 +80,48 @@ async def test_diagnostics_include_ocf_identity(
     assert identity['resources']['/oic/d']['rt'] == ['oic.wk.d', 'oic.d.refrigerator']
 
 
+async def test_diagnostics_include_oic_res_links(
+    hass: HomeAssistant, mock_entry, mock_coordinator_session
+) -> None:
+    """/oic/res -- OCF's resource-discovery endpoint -- rides along in
+    identity.raw the same way /oic/p and /oic/d do. Its response is a list
+    of Link objects (one per href/Collection the endpoint hosts), not a
+    single Property map, so redaction has to walk into the list too."""
+    from custom_components.localthings.registry.identity import DeviceIdentity
+
+    await hass.config_entries.async_setup(mock_entry.entry_id)
+    await hass.async_block_till_done()
+
+    coordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    coordinator._identity = DeviceIdentity(
+        manufacturer='Samsung Electronics',
+        model='RF9000B',
+        name='Family Hub',
+        serial=None,
+        device_types=('oic.wk.d', 'oic.d.refrigerator'),
+        raw={
+            '/oic/p': {'mnmn': 'Samsung Electronics'},
+            '/oic/d': {'rt': ['oic.wk.d', 'oic.d.refrigerator']},
+            '/oic/res': [
+                {'di': 'aaaa-1111', 'href': '/device/0',
+                 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+                {'di': 'bbbb-2222', 'href': '/device/1',
+                 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+            ],
+        },
+    )
+
+    diag = await async_get_config_entry_diagnostics(hass, mock_entry)
+
+    links = diag['identity']['resources']['/oic/res']
+    assert len(links) == 2
+    assert links[0]['di'] == REDACTED
+    assert links[0]['href'] == '/device/0'
+    assert links[1]['di'] == REDACTED
+    assert links[1]['href'] == '/device/1'
+    assert links[1]['rt'] == ['x.com.samsung.devcol', 'oic.wk.col']
+
+
 async def test_diagnostics_identity_none_when_unavailable(
     hass: HomeAssistant, mock_entry, mock_coordinator_session
 ) -> None:

tests/test_identity.py

@@ -32,7 +32,7 @@ def test_read_identity_tolerates_missing_resources():
     assert ident.model == ''
     assert ident.serial is None
     assert ident.device_types == ()
-    assert ident.raw == {'/oic/p': {}, '/oic/d': {}}
+    assert ident.raw == {'/oic/p': {}, '/oic/d': {}, '/oic/res': []}
 
 
 def test_read_identity_captures_oic_d_device_types():
@@ -69,3 +69,33 @@ def test_read_identity_keeps_raw_payloads_for_diagnostics():
     ident = read_identity(sess, serial=None)
     assert ident.raw['/oic/p']['mnmo'] == 'RF9000B'
     assert ident.raw['/oic/d']['di'] == 'abc-123'
+
+
+def test_read_identity_captures_oic_res_links():
+    """/oic/res is OCF's discovery endpoint: a baseline RETRIEVE returns an
+    array of Link objects, one per Resource/Collection the endpoint hosts --
+    including, per the OCF 'Composite Device' model, a second logical
+    Device's Collection on a multi-unit system (issue #177). Nothing routes
+    on this yet; captured so a report from such a device shows us whether
+    its firmware actually exposes more than the one /device/0 seed href."""
+    sess = FakeSession({
+        ('oic', 'res'): [
+            {'di': 'aaaa', 'href': '/device/0', 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+            {'di': 'bbbb', 'href': '/device/1', 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+        ],
+    })
+    ident = read_identity(sess, serial=None)
+    assert ident.raw['/oic/res'] == [
+        {'di': 'aaaa', 'href': '/device/0', 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+        {'di': 'bbbb', 'href': '/device/1', 'rt': ['x.com.samsung.devcol', 'oic.wk.col']},
+    ]
+
+
+def test_read_identity_tolerates_malformed_oic_res():
+    """A single Property map instead of an array (or anything else
+    non-list-shaped) must not explode -- same defensive posture as
+    _device_types' handling of a malformed /oic/d rt."""
+    ident = read_identity(
+        FakeSession({('oic', 'res'): {'not': 'a list'}}), serial=None
+    )
+    assert ident.raw['/oic/res'] == []