add copeland test

ia04/comsoc/cs_test.go

@@ -121,6 +121,42 @@ func TestApprovalSCF(t *testing.T) {
 	}
 }
 
+func TestCopelandSWF(t *testing.T) {
+	prefs := [][]Alternative{
+		{3, 1, 2}, // (1) = -1 -1 = -2 ; (2) = +1 -1 = 0 ; (3) = 2
+		{2, 1, 3},
+		{3, 2, 1},
+	}
+	res, _ := CopelandSWF(prefs)
+
+	if res[1] != -2 {
+		t.Errorf("error, result for 1 should be -2, %d computed", res[1])
+	}
+	if res[2] != 0 {
+		t.Errorf("error, result for 2 should be 0, %d computed", res[2])
+	}
+	if res[3] != 2 {
+		t.Errorf("error, result for 3 should be 2, %d computed", res[3])
+	}
+}
+
+func TestCopelandSCF(t *testing.T) {
+	prefs := [][]Alternative{
+		{3, 1, 2},
+		{2, 1, 3},
+		{3, 2, 1},
+	}
+
+	res, err := CopelandSCF(prefs)
+
+	if err != nil {
+		t.Error(err)
+	}
+	if len(res) != 1 || res[0] != 3 {
+		t.Errorf("error, 3 should be the only best Alternative")
+	}
+}
+
 func TestCondorcetWinner(t *testing.T) {
 	prefs1 := [][]Alternative{
 		{1, 2, 3},