diff --git a/tests/fixture/tmpnet/subnet.go b/tests/fixture/tmpnet/subnet.go
index cbff01585e20..55979a2eb81c 100644
--- a/tests/fixture/tmpnet/subnet.go
+++ b/tests/fixture/tmpnet/subnet.go
@@ -25,7 +25,10 @@ import (
 	"github.com/ava-labs/avalanchego/wallet/subnet/primary/common"
 )
 
-const defaultSubnetDirName = "subnets"
+const (
+	defaultSubnetDirName = "subnets"
+	jsonFileSuffix       = ".json"
+)
 
 type Chain struct {
 	// Set statically
@@ -209,7 +212,7 @@ func (s *Subnet) Write(subnetDir string, chainDir string) error {
 	if err := os.MkdirAll(subnetDir, perms.ReadWriteExecute); err != nil {
 		return fmt.Errorf("failed to create subnet dir: %w", err)
 	}
-	tmpnetConfigPath := filepath.Join(subnetDir, s.Name+".json")
+	tmpnetConfigPath := filepath.Join(subnetDir, s.Name+jsonFileSuffix)
 
 	// Since subnets are expected to be serialized for the first time
 	// without their chains having been created (i.e. chains will have
@@ -249,13 +252,8 @@ func (s *Subnet) Write(subnetDir string, chainDir string) error {
 			return fmt.Errorf("failed to marshal avalanchego subnet config %s: %w", s.Name, err)
 		}
 
-		avgoConfigDir := filepath.Join(subnetDir, s.SubnetID.String())
-		if err := os.MkdirAll(avgoConfigDir, perms.ReadWriteExecute); err != nil {
-			return fmt.Errorf("failed to create avalanchego subnet config dir: %w", err)
-		}
-
-		avgoConfigPath := filepath.Join(avgoConfigDir, defaultConfigFilename)
-		if err := os.WriteFile(avgoConfigPath, bytes, perms.ReadWrite); err != nil {
+		subnetConfigPath := filepath.Join(subnetDir, s.SubnetID.String()+jsonFileSuffix)
+		if err := os.WriteFile(subnetConfigPath, bytes, perms.ReadWrite); err != nil {
 			return fmt.Errorf("failed to write avalanchego subnet config %s: %w", s.Name, err)
 		}
 	}
@@ -351,7 +349,7 @@ func readSubnets(subnetDir string) ([]*Subnet, error) {
 			// Looking only for files
 			continue
 		}
-		if filepath.Ext(entry.Name()) != ".json" {
+		if filepath.Ext(entry.Name()) != jsonFileSuffix {
 			// Subnet files should have a .json extension
 			continue
 		}