token_test.go: rewritten using a more structured form

token_test.go

@@ -5,14 +5,34 @@
 package expr
 
 import (
-	"fmt"
 	"testing"
 )
 
 func TestDevString(t *testing.T) {
-	tk1 := NewValueToken(0, 0, SymInteger, "100", 100)
-	tk2 := NewToken(0, 0, SymPlus, "+")
+	type inputType struct {
+		source     string
+		sym        Symbol
+		value      any
+		wantResult string
+	}
 
-	fmt.Println("Token '100':", tk1.DevString())
-	fmt.Println("Token '+':", tk2.DevString())
+	inputs := []inputType{
+		/*   1 */ {"100", SymInteger, 100, `[55]"100"{100}`},
+		/*   2 */ {"+", SymPlus, nil, `[6]"+"{}`},
+	}
+
+	for i, input := range inputs {
+		var tk *Token
+		if input.value == nil {
+			tk = NewToken(0, 0, input.sym, input.source)
+		} else {
+			tk = NewValueToken(0, 0, input.sym, input.source, input.value)
+		}
+
+		t.Logf("Test nr %2d: %q --> %q", i+1, input.source, input.wantResult)
+
+		if s := tk.DevString(); s != input.wantResult {
+			t.Errorf("wrong token from symbol '+': expected %q, got %q", input.wantResult, s)
+		}
+	}
 }