cec2020: add TestSchafferExpanded

bench/cec2020/basicFunctions_test.go

@@ -155,3 +155,33 @@ func TestAckley(t *testing.T) {
 		t.Errorf("incorrect output, want: %f, got: %v", want, got)
 	}
 }
+
+func TestSchafferExpanded(t *testing.T) {
+	testInput := []float64{
+		-2.7137778065280593,
+		-1.9789783390895765,
+		-4.38267902085263,
+		-4.617877608383319,
+		-2.1529909200665474,
+		-3.801849324611571,
+		2.4968697503272486,
+		-0.27358100201730196,
+		2.0444319451255977,
+		3.8798952350630653,
+		-0.6150024279011337,
+		2.8643010641852413,
+		-0.6692444051928748,
+		4.4649633199687475,
+		3.2510298731558507,
+		-4.2095036422081495,
+		-0.130882052243404,
+		1.2001716295708604,
+		-0.29427650577602193,
+	}
+	want := 15.903821248304322
+	got := SchafferExpanded(testInput)
+
+	if want != got {
+		t.Errorf("incorrect output, want: %f, got: %v", want, got)
+	}
+}