diff --git a/cmd/zetatool/config/config.go b/cmd/zetatool/config/config.go
index eac4d4e2f7..1fbf991a66 100644
--- a/cmd/zetatool/config/config.go
+++ b/cmd/zetatool/config/config.go
@@ -2,21 +2,24 @@ package config
 
 import (
 	"encoding/json"
-	"os"
+
+	"github.com/spf13/afero"
 )
 
+var AppFs = afero.NewOsFs()
+
 const (
-	Flag               = "config"
-	defaultCfgFileName = "InboundTxFilter_config.json"
-	ZetaURL            = "http://46.4.15.110:1317" //http://100.71.167.102:26657
-	TssAddressBTC      = "bc1qm24wp577nk8aacckv8np465z3dvmu7ry45el6y"
-	TssAddressEVM      = "0x70e967acfcc17c3941e87562161406d41676fd83"
-	BtcExplorer        = "https://blockstream.info/api/address/bc1qm24wp577nk8aacckv8np465z3dvmu7ry45el6y/txs"
-	EthRPC             = "https://rpc.ankr.com/eth/2da24e4a1fd28f2bec1569eceb2c38a5694b7f5c83fd24c69ae714a89a514f9b"
-	ConnectorAddress   = "0x000007Cf399229b2f5A4D043F20E90C9C98B7C6a"
-	CustodyAddress     = "0x0000030Ec64DF25301d8414eE5a29588C4B0dE10"
-	EvmStartBlock      = 19200110
-	EvmMaxRange        = 1000
+	Flag                      = "config"
+	defaultCfgFileName        = "InboundTxFilter_config.json"
+	ZetaURL                   = "http://46.4.15.110:1317" //http://100.71.167.102:26657
+	TssAddressBTC             = "bc1qm24wp577nk8aacckv8np465z3dvmu7ry45el6y"
+	TssAddressEVM             = "0x70e967acfcc17c3941e87562161406d41676fd83"
+	BtcExplorer               = "https://blockstream.info/api/address/bc1qm24wp577nk8aacckv8np465z3dvmu7ry45el6y/txs"
+	EthRPC                    = "https://rpc.ankr.com/eth/2da24e4a1fd28f2bec1569eceb2c38a5694b7f5c83fd24c69ae714a89a514f9b"
+	ConnectorAddress          = "0x000007Cf399229b2f5A4D043F20E90C9C98B7C6a"
+	CustodyAddress            = "0x0000030Ec64DF25301d8414eE5a29588C4B0dE10"
+	EvmStartBlock      uint64 = 19200110
+	EvmMaxRange        uint64 = 1000
 )
 
 type Config struct {
@@ -50,12 +53,12 @@ func (c *Config) Save() error {
 	if err != nil {
 		return err
 	}
-	err = os.WriteFile(defaultCfgFileName, file, 0600)
+	err = afero.WriteFile(AppFs, defaultCfgFileName, file, 0600)
 	return err
 }
 
 func (c *Config) Read(filename string) error {
-	data, err := os.ReadFile(filename)
+	data, err := afero.ReadFile(AppFs, filename)
 	if err != nil {
 		return err
 	}
diff --git a/cmd/zetatool/config/config_test.go b/cmd/zetatool/config/config_test.go
new file mode 100644
index 0000000000..1dda4936ce
--- /dev/null
+++ b/cmd/zetatool/config/config_test.go
@@ -0,0 +1,80 @@
+package config
+
+import (
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestDefaultConfig(t *testing.T) {
+	cfg := DefaultConfig()
+	require.Equal(t, cfg.EthRPC, EthRPC)
+	require.Equal(t, cfg.ZetaURL, ZetaURL)
+	require.Equal(t, cfg.TssAddressBTC, TssAddressBTC)
+	require.Equal(t, cfg.TssAddressEVM, TssAddressEVM)
+	require.Equal(t, cfg.BtcExplorer, BtcExplorer)
+	require.Equal(t, cfg.ConnectorAddress, ConnectorAddress)
+	require.Equal(t, cfg.CustodyAddress, CustodyAddress)
+	require.Equal(t, cfg.EvmStartBlock, EvmStartBlock)
+	require.Equal(t, cfg.EvmMaxRange, EvmMaxRange)
+}
+
+func TestGetConfig(t *testing.T) {
+	AppFs = afero.NewMemMapFs()
+	defaultCfg := DefaultConfig()
+
+	t.Run("No config file specified", func(t *testing.T) {
+		cfg, err := GetConfig("")
+		require.NoError(t, err)
+		require.Equal(t, cfg, defaultCfg)
+
+		exists, err := afero.Exists(AppFs, defaultCfgFileName)
+		require.NoError(t, err)
+		require.True(t, exists)
+	})
+
+	t.Run("config file specified", func(t *testing.T) {
+		cfg, err := GetConfig(defaultCfgFileName)
+		require.NoError(t, err)
+		require.Equal(t, cfg, defaultCfg)
+	})
+}
+
+func TestConfig_Read(t *testing.T) {
+	AppFs = afero.NewMemMapFs()
+	cfg, err := GetConfig("")
+	require.NoError(t, err)
+
+	t.Run("read existing file", func(t *testing.T) {
+		c := &Config{}
+		err := c.Read(defaultCfgFileName)
+		require.NoError(t, err)
+		require.Equal(t, c, cfg)
+	})
+
+	t.Run("read non-existent file", func(t *testing.T) {
+		err := AppFs.Remove(defaultCfgFileName)
+		require.NoError(t, err)
+		c := &Config{}
+		err = c.Read(defaultCfgFileName)
+		require.ErrorContains(t, err, "file does not exist")
+		require.NotEqual(t, c, cfg)
+	})
+}
+
+func TestConfig_Save(t *testing.T) {
+	AppFs = afero.NewMemMapFs()
+	cfg := DefaultConfig()
+	cfg.EvmMaxRange = uint64(2000)
+
+	t.Run("save modified cfg", func(t *testing.T) {
+		err := cfg.Save()
+		require.NoError(t, err)
+
+		newCfg, err := GetConfig(defaultCfgFileName)
+		require.NoError(t, err)
+		require.Equal(t, cfg, newCfg)
+	})
+
+	// Should test invalid json encoding but currently not able to without interface
+}