add convenience method

backend/src/main/java/de/cotto/lndmanagej/service/NodeWarningsService.java

@@ -45,12 +45,8 @@ public class NodeWarningsService {
                 .map(LocalChannel::getRemotePubkey)
                 .distinct()
                 .map(pubkey -> new AbstractMap.SimpleEntry<>(pubkey, getNodeWarnings(pubkey)))
-                .filter(this::hasWarnings)
+                .filter(entry -> entry.getValue().hasWarnings())
                 .map(entry -> new AbstractMap.SimpleEntry<>(nodeService.getNode(entry.getKey()), entry.getValue()))
                 .collect(toMap(Entry::getKey, Entry::getValue));
     }
-
-    private boolean hasWarnings(Entry<?, NodeWarnings> entry) {
-        return !entry.getValue().warnings().isEmpty();
-    }
 }

model/src/main/java/de/cotto/lndmanagej/model/warnings/NodeWarnings.java

@@ -14,4 +14,8 @@ public record NodeWarnings(Set<NodeWarning> warnings) {
     public Set<String> descriptions() {
         return warnings.stream().map(NodeWarning::description).collect(Collectors.toSet());
     }
+
+    public boolean hasWarnings() {
+        return !warnings.isEmpty();
+    }
 }

model/src/test/java/de/cotto/lndmanagej/model/warnings/NodeWarningsTest.java

@@ -33,4 +33,14 @@ class NodeWarningsTest {
     void none() {
         assertThat(NodeWarnings.NONE).isEqualTo(new NodeWarnings(Set.of()));
     }
-}
+
+    @Test
+    void hasWarnings_empty() {
+        assertThat(NodeWarnings.NONE.hasWarnings()).isFalse();
+    }
+
+    @Test
+    void hasWarnings_several_warnings() {
+        assertThat(NODE_WARNINGS.hasWarnings()).isTrue();
+    }
+}