Add toString() methods to WOT network classes

pgpainless-wot/src/main/java/org/pgpainless/wot/WebOfTrust.java

@@ -157,4 +157,9 @@ public class WebOfTrust implements CertificateAuthority {
     public boolean isAuthorized(PGPPublicKeyRing certificate, String userId) {
         return false;
     }
+
+    @Override
+    public String toString() {
+        return network.toString();
+    }
 }

wot-dijkstra/src/main/java/org/pgpainless/wot/dijkstra/sq/CertSynopsis.java

@@ -71,4 +71,9 @@ public class CertSynopsis {
     public Set<String> userIds() {
         return new HashSet<>(userIds);
     }
+
+    @Override
+    public String toString() {
+        return fingerprint + (userIds.isEmpty() ? "" : "(" + userIds.iterator().next() + ")");
+    }
 }

wot-dijkstra/src/main/java/org/pgpainless/wot/dijkstra/sq/Certification.java

@@ -166,4 +166,13 @@ public class Certification {
     public RegexSet getRegexes() {
         return regex;
     }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(issuer.getFingerprint()).append((issuer.userIds().isEmpty() ? " " : " (" + issuer.userIds().iterator().next() + ") "));
+        sb.append(userId.isPresent() ? "certifies" : "delegates to").append(userId.isPresent() ? " [" + userId.get() + "] " : " ").append(target.getFingerprint())
+                .append(userId.isEmpty() && !target.userIds().isEmpty() ? " (" + target.userIds().iterator().next() + ")" : "");
+        return sb.toString();
+    }
 }

wot-dijkstra/src/main/java/org/pgpainless/wot/dijkstra/sq/CertificationSet.java

@@ -110,4 +110,15 @@ public final class CertificationSet {
         // TODO: Prevent duplicates, only keep newest timestamped sig?
         certificationsForUserId.add(certification);
     }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        for (Map.Entry<Optional<String>, List<Certification>> entry : certifications.entrySet()) {
+            for (Certification certification : entry.getValue()) {
+                sb.append(certification).append("\n");
+            }
+        }
+        return sb.toString();
+    }
 }

wot-dijkstra/src/main/java/org/pgpainless/wot/dijkstra/sq/Network.java

@@ -58,4 +58,13 @@ public class Network {
         return referenceTime;
     }
 
-}
+    public String toString() {
+        StringBuilder sb = new StringBuilder("Network with " + getNodes().size() + " nodes, " + getEdges().size() + " edges:\n");
+        for (OpenPgpFingerprint issuer : getNodes().keySet()) {
+            for (CertificationSet edge : getReverseEdges().get(issuer)) {
+                sb.append(edge);
+            }
+        }
+        return sb.toString();
+    }
+}