tests with multiple common friends

src/main/java/io/github/danthe1st/arebac/data/graph_pattern/GPGraph.java

@@ -1,5 +1,6 @@
 package io.github.danthe1st.arebac.data.graph_pattern;
 
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -22,8 +23,8 @@ public record GPGraph(Map<String, GPNode> nodes,
 	public GPGraph(List<GPNode> nodes, List<GPEdge> edges) {
 		this(
 				nodes.stream().collect(Collectors.toMap(GPNode::id, Function.identity())),
-				edges.stream().collect(Collectors.groupingBy(GPEdge::source)),
-				edges.stream().collect(Collectors.groupingBy(GPEdge::target))
+				edges.stream().collect(Collectors.groupingBy(GPEdge::source, LinkedHashMap::new, Collectors.toList())),
+				edges.stream().collect(Collectors.groupingBy(GPEdge::target, LinkedHashMap::new, Collectors.toList()))
 		);
 	}
 

src/test/java/io/github/danthe1st/arebac/tests/weaving/MultipleCommonFriendsWeavingTest.java

@@ -0,0 +1,89 @@
+package io.github.danthe1st.arebac.tests.weaving;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Map;
+
+import io.github.danthe1st.arebac.data.graph_pattern.GPEdge;
+import io.github.danthe1st.arebac.data.graph_pattern.GPGraph;
+import io.github.danthe1st.arebac.data.graph_pattern.GPNode;
+import io.github.danthe1st.arebac.data.graph_pattern.GraphPattern;
+import io.github.danthe1st.arebac.data.graph_pattern.constraints.MutualExclusionConstraint;
+import io.github.danthe1st.arebac.weaving.Weaving;
+import org.junit.jupiter.api.Test;
+
+class MultipleCommonFriendsWeavingTest {
+	private static final String FRIEND_EDGE_TYPE = "friend";
+	private static final String USER_NODE_TYPE = "user";
+
+	@Test
+	void testCombineFriendsOfFriendsWithNotSelf() {
+		GraphPattern combined = Weaving.combinePatterns(List.of(createCommonFriendsPattern(), createRequestorNotTargetPattern()));
+		assertEquals(createExpectedCombinedFriendsOfFriendsButNotSelfPattern(), combined);
+	}
+
+	private GraphPattern createExpectedCombinedFriendsOfFriendsButNotSelfPattern() {
+		GPNode requestor = new GPNode("p0,requestor", USER_NODE_TYPE);
+		GPNode target = new GPNode("p0,target", USER_NODE_TYPE);
+		GPNode firstFriend = new GPNode("p0,f1", USER_NODE_TYPE);
+		GPNode secondFriend = new GPNode("p0,f2", USER_NODE_TYPE);
+
+		return new GraphPattern(
+				new GPGraph(
+						List.of(requestor, target, firstFriend, secondFriend),
+						List.of(
+								new GPEdge(requestor, firstFriend, "p0,req->f1", FRIEND_EDGE_TYPE),
+								new GPEdge(requestor, secondFriend, "p0,req->f2", FRIEND_EDGE_TYPE),
+								new GPEdge(firstFriend, target, "p0,f1->target", FRIEND_EDGE_TYPE),
+								new GPEdge(secondFriend, target, "p0,f2->target", FRIEND_EDGE_TYPE)
+						)
+				),
+				List.of(
+						new MutualExclusionConstraint(firstFriend, secondFriend),
+						new MutualExclusionConstraint(requestor, target)
+				),
+				Map.of(),
+				Map.of(),
+				List.of(target),
+				Map.of("requestor", requestor, "target", target)
+		);
+	}
+
+	private GraphPattern createRequestorNotTargetPattern() {
+		GPNode requestor = new GPNode("requestor", USER_NODE_TYPE);
+		GPNode target = new GPNode("target", USER_NODE_TYPE);
+
+		return new GraphPattern(
+				new GPGraph(List.of(requestor, target), List.of()),
+				List.of(new MutualExclusionConstraint(requestor, target)),
+				Map.of(),
+				Map.of(),
+				List.of(),
+				Map.of("requestor", requestor, "target", target)
+		);
+	}
+
+	private GraphPattern createCommonFriendsPattern() {
+		GPNode requestor = new GPNode("requestor", USER_NODE_TYPE);
+		GPNode target = new GPNode("target", USER_NODE_TYPE);
+		GPNode firstFriend = new GPNode("f1", USER_NODE_TYPE);
+		GPNode secondFriend = new GPNode("f2", USER_NODE_TYPE);
+
+		return new GraphPattern(
+				new GPGraph(
+						List.of(requestor, target, firstFriend, secondFriend),
+						List.of(
+								new GPEdge(requestor, firstFriend, "req->f1", FRIEND_EDGE_TYPE),
+								new GPEdge(requestor, secondFriend, "req->f2", FRIEND_EDGE_TYPE),
+								new GPEdge(firstFriend, target, "f1->target", FRIEND_EDGE_TYPE),
+								new GPEdge(secondFriend, target, "f2->target", FRIEND_EDGE_TYPE)
+						)
+				), List.of(new MutualExclusionConstraint(firstFriend, secondFriend)),
+				Map.of(),
+				Map.of(),
+				List.of(target),
+				Map.of("requestor", requestor, "target", target)
+		);
+	}
+}

src/test/java/io/github/danthe1st/arebac/tests/weaving/MultiplePatternsReturnSameNodeTest.java

@@ -0,0 +1,35 @@
+package io.github.danthe1st.arebac.tests.weaving;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import java.util.Map;
+
+import io.github.danthe1st.arebac.data.graph_pattern.GPGraph;
+import io.github.danthe1st.arebac.data.graph_pattern.GPNode;
+import io.github.danthe1st.arebac.data.graph_pattern.GraphPattern;
+import io.github.danthe1st.arebac.weaving.Weaving;
+import org.junit.jupiter.api.Test;
+
+class MultiplePatternsReturnSameNodeTest {
+	@Test
+    void testMeregPatternsReturnSameResult() {
+        GPNode singleNode = new GPNode("someNode", "user");
+		GraphPattern simplePattern = new GraphPattern(
+				new GPGraph(List.of(singleNode), List.of()),
+				List.of(), Map.of(), Map.of(),
+				List.of(singleNode),
+				Map.of("relevantNode", singleNode)
+		);
+		GraphPattern combinedWithItself = Weaving.combinePatterns(List.of(simplePattern, simplePattern));
+
+		GPNode nodeInResult = new GPNode("p0,someNode", "user");
+		GraphPattern expectedPattern = new GraphPattern(
+				new GPGraph(List.of(nodeInResult), List.of()),
+				List.of(), Map.of(), Map.of(),
+				List.of(nodeInResult, nodeInResult),
+				Map.of("relevantNode", nodeInResult)
+		);
+		assertEquals(expectedPattern, combinedWithItself);
+    }
+}