diff --git a/src/test/resources/queries/relation/focus-empty-both.json b/src/test/resources/queries/relation/focus-empty-both.json
new file mode 100644
index 0000000..1e9fa16
--- /dev/null
+++ b/src/test/resources/queries/relation/focus-empty-both.json
@@ -0,0 +1,39 @@
+{
+    "query": {
+        "@type": "koral:reference",
+        "operation": "operation:focus",
+        "classRef": [2],
+        "operands": [{
+            "@type": "koral:group",
+            "operation": "operation:relation",
+            "operands": [
+                {
+                   "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 1,
+                    "operands": [{
+                        "@type": "koral:token"
+                    }]
+                },
+                {
+                    "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 2,
+                    "operands": [{
+                        "@type": "koral:token"
+                    }]
+                }
+            ],
+            "relation": {
+                "@type": "koral:relation",
+                "wrap": {
+                    "@type": "koral:term",
+                    "foundry": "mate",
+                    "layer": "d",
+                    "key": "HEAD"
+                }
+            }
+        }]
+    },
+    "meta": {}
+}
diff --git a/src/test/resources/queries/relation/focus-empty-target.json b/src/test/resources/queries/relation/focus-empty-target.json
new file mode 100644
index 0000000..78ac125
--- /dev/null
+++ b/src/test/resources/queries/relation/focus-empty-target.json
@@ -0,0 +1,42 @@
+{
+    "query": {
+        "@type": "koral:reference",
+        "operation": "operation:focus",
+        "classRef": [2],
+        "operands": [{
+            "@type": "koral:group",
+            "operation": "operation:relation",
+            "operands": [
+                {
+                   "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 1,
+                    "operands": [{
+                        "@type": "koral:span",
+                        "layer": "c",
+                        "key": "s",
+                        "match": "match:eq"
+                    }]
+                },
+                {
+                    "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 2,
+                    "operands": [{
+                        "@type": "koral:token"
+                    }]
+                }
+            ],
+            "relation": {
+                "@type": "koral:relation",
+                "wrap": {
+                    "@type": "koral:term",
+                    "foundry": "mate",
+                    "layer": "d",
+                    "key": "HEAD"
+                }
+            }
+        }]
+    },
+    "meta": {}
+}
diff --git a/src/test/resources/queries/relation/focus-source.json b/src/test/resources/queries/relation/focus-source.json
index d934a3b..68d5ce4 100644
--- a/src/test/resources/queries/relation/focus-source.json
+++ b/src/test/resources/queries/relation/focus-source.json
@@ -11,8 +11,15 @@
                     "@type": "koral:token"
                 },
                 {
-                    "@type": "koral:span",
-                    "key": "np"
+                   "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 1,
+                    "operands": [{
+                        "@type": "koral:span",
+                        "layer": "c",
+                        "key": "np",
+                        "match": "match:eq"
+                    }]
                 }
             ],
             "relation": {
diff --git a/src/test/resources/queries/relation/focus-target.json b/src/test/resources/queries/relation/focus-target.json
index daec972..46282a8 100644
--- a/src/test/resources/queries/relation/focus-target.json
+++ b/src/test/resources/queries/relation/focus-target.json
@@ -8,11 +8,26 @@
             "operation": "operation:relation",
             "operands": [
                 {
-                    "@type": "koral:span",
-                    "key": "s"
+                   "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 1,
+                    "operands": [{
+                        "@type": "koral:span",
+                        "layer": "c",
+                        "key": "s",
+                        "match": "match:eq"
+                    }]
                 },
                 {
-                    "@type": "koral:token"
+                    "@type": "koral:group",
+                    "operation": "operation:class",
+                    "classOut": 2,
+                    "operands": [{
+                        "@type": "koral:span",
+                        "layer": "c",
+                        "key": "np",
+                        "match": "match:eq"
+                    }]
                 }
             ],
             "relation": {