diff --git a/assets/config-invalid.toml b/assets/config-invalid.toml
new file mode 100644
index 0000000..8c1b662
--- /dev/null
+++ b/assets/config-invalid.toml
@@ -0,0 +1 @@
+[[chains]]
diff --git a/cmd/missed-blocks-checker.go b/cmd/missed-blocks-checker.go
index 0420c65..c1b8b41 100644
--- a/cmd/missed-blocks-checker.go
+++ b/cmd/missed-blocks-checker.go
@@ -1,46 +1,33 @@
 package main
 
 import (
+	"github.com/spf13/cobra"
 	"main/pkg"
 	configPkg "main/pkg/config"
 	"main/pkg/fs"
 	"main/pkg/logger"
-	"os"
-
-	"github.com/spf13/cobra"
 )
 
 var (
 	version = "unknown"
 )
 
-type OsFS struct {
-}
-
-func (fs *OsFS) ReadFile(name string) ([]byte, error) {
-	return os.ReadFile(name)
-}
-
-func (fs *OsFS) Create(path string) (fs.File, error) {
-	return os.Create(path)
-}
-
 func ExecuteMain(configPath string) {
-	filesystem := &OsFS{}
+	filesystem := &fs.OsFS{}
 	app := pkg.NewApp(configPath, filesystem, version)
 	app.Start()
 }
 
 func ExecuteValidateConfig(configPath string) {
-	filesystem := &OsFS{}
+	filesystem := &fs.OsFS{}
 
 	config, err := configPkg.GetConfig(configPath, filesystem)
 	if err != nil {
-		logger.GetDefaultLogger().Fatal().Err(err).Msg("Could not load config!")
+		logger.GetDefaultLogger().Panic().Err(err).Msg("Could not load config!")
 	}
 
 	if err := config.Validate(); err != nil {
-		logger.GetDefaultLogger().Fatal().Err(err).Msg("Config is invalid!")
+		logger.GetDefaultLogger().Panic().Err(err).Msg("Config is invalid!")
 	}
 
 	logger.GetDefaultLogger().Info().Msg("Provided config is valid.")
@@ -68,18 +55,14 @@ func main() {
 	}
 
 	rootCmd.PersistentFlags().StringVar(&ConfigPath, "config", "", "Config file path")
-	if err := rootCmd.MarkPersistentFlagRequired("config"); err != nil {
-		logger.GetDefaultLogger().Fatal().Err(err).Msg("Could not set flag as required")
-	}
+	_ = rootCmd.MarkPersistentFlagRequired("config")
 
 	validateConfigCmd.PersistentFlags().StringVar(&ConfigPath, "config", "", "Config file path")
-	if err := validateConfigCmd.MarkPersistentFlagRequired("config"); err != nil {
-		logger.GetDefaultLogger().Fatal().Err(err).Msg("Could not set flag as required")
-	}
+	_ = validateConfigCmd.MarkPersistentFlagRequired("config")
 
 	rootCmd.AddCommand(validateConfigCmd)
 
 	if err := rootCmd.Execute(); err != nil {
-		logger.GetDefaultLogger().Fatal().Err(err).Msg("Could not start application")
+		logger.GetDefaultLogger().Panic().Err(err).Msg("Could not start application")
 	}
 }
diff --git a/cmd/missed-blocks-checker_test.go b/cmd/missed-blocks-checker_test.go
new file mode 100644
index 0000000..62fb7bb
--- /dev/null
+++ b/cmd/missed-blocks-checker_test.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+//nolint:paralleltest // disabled
+func TestValidateConfigNoConfigProvided(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			require.Fail(t, "Expected to have a panic here!")
+		}
+	}()
+
+	os.Args = []string{"cmd", "validate-config"}
+	main()
+	assert.True(t, true)
+}
+
+//nolint:paralleltest // disabled
+func TestValidateConfigFailedToLoad(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			require.Fail(t, "Expected to have a panic here!")
+		}
+	}()
+
+	os.Args = []string{"cmd", "validate-config", "--config", "../assets/config-not-found.toml"}
+	main()
+	assert.True(t, true)
+}
+
+//nolint:paralleltest // disabled
+func TestValidateConfigInvalid(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			require.Fail(t, "Expected to have a panic here!")
+		}
+	}()
+
+	os.Args = []string{"cmd", "validate-config", "--config", "../assets/config-invalid.toml"}
+	main()
+	assert.True(t, true)
+}
+
+//nolint:paralleltest // disabled
+func TestValidateConfigValid(t *testing.T) {
+	os.Args = []string{"cmd", "validate-config", "--config", "../assets/valid.toml"}
+	main()
+	assert.True(t, true)
+}
+
+//nolint:paralleltest // disabled
+func TestStartNoConfigProvided(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			require.Fail(t, "Expected to have a panic here!")
+		}
+	}()
+
+	os.Args = []string{"cmd"}
+	main()
+	assert.True(t, true)
+}
+
+//nolint:paralleltest // disabled
+func TestStartConfigProvided(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			require.Fail(t, "Expected to have a panic here!")
+		}
+	}()
+
+	os.Args = []string{"cmd", "--config", "../assets/config-invalid.toml"}
+	main()
+	assert.True(t, true)
+}
diff --git a/pkg/app.go b/pkg/app.go
index 9863a3c..bdc42bb 100644
--- a/pkg/app.go
+++ b/pkg/app.go
@@ -23,11 +23,11 @@ type App struct {
 func NewApp(configPath string, filesystem fs.FS, version string) *App {
 	config, err := configPkg.GetConfig(configPath, filesystem)
 	if err != nil {
-		loggerPkg.GetDefaultLogger().Fatal().Err(err).Msg("Could not load config")
+		loggerPkg.GetDefaultLogger().Panic().Err(err).Msg("Could not load config")
 	}
 
 	if err = config.Validate(); err != nil {
-		loggerPkg.GetDefaultLogger().Fatal().Err(err).Msg("Provided config is invalid!")
+		loggerPkg.GetDefaultLogger().Panic().Err(err).Msg("Provided config is invalid!")
 	}
 
 	for _, chainConfig := range config.ChainConfigs {
diff --git a/pkg/fs/os_fs.go b/pkg/fs/os_fs.go
new file mode 100644
index 0000000..59e46ca
--- /dev/null
+++ b/pkg/fs/os_fs.go
@@ -0,0 +1,14 @@
+package fs
+
+import "os"
+
+type OsFS struct {
+}
+
+func (fs *OsFS) ReadFile(name string) ([]byte, error) {
+	return os.ReadFile(name)
+}
+
+func (fs *OsFS) Create(path string) (File, error) {
+	return os.Create(path)
+}
diff --git a/pkg/fs/os_fs_test.go b/pkg/fs/os_fs_test.go
new file mode 100644
index 0000000..dfc478f
--- /dev/null
+++ b/pkg/fs/os_fs_test.go
@@ -0,0 +1,15 @@
+package fs
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestOsFsCreate(t *testing.T) {
+	t.Parallel()
+
+	fs := &OsFS{}
+	_, err := fs.Create("/tmp/file.txt")
+	require.NoError(t, err)
+}