community: fix tests

community/louvain_test.go

@@ -211,6 +211,15 @@ func reverse(f []float64) {
 	}
 }
 
+func hasNegative(f []float64) bool {
+	for _, v := range f {
+		if v < 0 {
+			return true
+		}
+	}
+	return false
+}
+
 var (
 	dupGraph         = simple.NewUndirectedGraph(0, 0)
 	dupGraphDirected = simple.NewDirectedGraph(0, 0)

community/louvain_undirected_multiplex_test.go

@@ -346,10 +346,14 @@ tests:
 					if i == communityOf[target.ID()] {
 						continue
 					}
-					if !all {
+					if !(all && hasNegative(weights)) {
 						connected := false
 					search:
 						for l := 0; l < g.Depth(); l++ {
+							if weights[l] < 0 {
+								connected = true
+								break search
+							}
 							layer := g.Layer(l)
 							for n := range c {
 								if layer.HasEdgeBetween(simple.Node(n), target) {