diff --git a/error.go b/error.go
index 03d67d4..7aee285 100644
--- a/error.go
+++ b/error.go
@@ -62,10 +62,6 @@ func GetError(err error) (Err *Error) {
 		return custom
 	}
 
-	if unwrapped := errors.Unwrap(err); unwrapped != nil {
-		return GetError(unwrapped)
-	}
-
 	return &Error{msg: err.Error(), cause: err}
 }
 
@@ -97,6 +93,12 @@ func Cause(err error) error {
 
 // Format is implement the fmt.Formatter for Error.
 func (e *Error) Format(state fmt.State, verb rune) {
+	if len(e.fields) == 0 {
+		fmt.Fprint(state, e.Error())
+
+		return
+	}
+
 	switch verb {
 	case 'v':
 		if state.Flag('+') {
diff --git a/error_test.go b/error_test.go
index cf51b98..3a816dc 100644
--- a/error_test.go
+++ b/error_test.go
@@ -1,82 +1,177 @@
 package errors_test
 
 import (
+	stdErrors "errors"
+	"fmt"
 	"testing"
 
 	"github.com/mrsoftware/errors"
+	"github.com/stretchr/testify/assert"
 )
 
-func TestMy(t *testing.T) {
-	stValue := struct {
-		Username string
-		Password string
-	}{Username: "mrsoftware", Password: "kanman"}
-	err := errors.New("my error", errors.String("myString", "string value"), errors.Reflect("user", stValue))
+func TestNew(t *testing.T) {
+	t.Parallel()
 
-	// t.Logf("%q", err)
-	// t.Logf("%s", err)
-	// t.Logf("%v", err)
-	t.Logf("%+s", err)
+	msg := "some message"
 
-	t.Fail()
+	err := errors.New(msg)
+	assert.Equal(t, msg, err.Error())
 }
 
-//
-// func TestNew(t *testing.T) {
-// 	msg := "some message"
-//
-// 	err := errors.New(msg)
-// 	assert.Equal(t, msg, err.Error())
-// }
-//
-// func TestGetError(t *testing.T) {
-// 	var (
-// 		msg    = "some message"
-// 		fields = []errors.Field{{}}
-// 	)
-//
-// 	err := errors.New(msg, fields...)
-// 	assert.Equal(t, fields, errors.GetFields(err))
-// }
-//
-// func TestGetErrorNotCompatible(t *testing.T) {
-// 	var (
-// 		msg    = "some message"
-// 		fields = []errors.Field{{}}
-// 	)
-// 	mainErr := errors.New(msg, fields...)
-// 	err := fmt.Errorf("msg", mainErr)
-// 	assert.Equal(t, mainErr, errors.GetError(err))
-// }
-//
-// func TestWrap(t *testing.T) {
-// 	msg := "some message"
-// 	cErr := stdErr.New("cause")
-//
-// 	err := errors.Wrap(cErr, msg)
-// 	assert.Equal(t, "some message: cause", err.Error())
-// }
-//
-// func TestWrapf(t *testing.T) {
-// 	format := "some message id: %d"
-// 	cErr := stdErr.New("cause")
-//
-// 	err := errors.Wrapf(cErr, format, 10)
-// 	assert.Equal(t, "some message id: 10: cause", err.Error())
-// }
-//
-// func TestErrorf(t *testing.T) {
-// 	format := "some message id: %d"
-//
-// 	err := errors.Errorf(format, 10)
-// 	assert.Equal(t, "some message id: 10", err.Error())
-// }
-//
-// func TestErrorfWithFields(t *testing.T) {
-// 	format := "some message id: %d"
-// 	fields := []errors.Field{{}}
-//
-// 	err := errors.ErrorfWithFields(format, []interface{}{10}, fields...)
-// 	assert.Equal(t, "some message id: 10", err.Error())
-// 	assert.Equal(t, fields, errors.GetFields(err))
-// }
+func TestGetError(t *testing.T) {
+	t.Parallel()
+
+	t.Run("compatible error", func(t *testing.T) {
+		t.Parallel()
+
+		var (
+			msg    = "some message"
+			fields = []errors.Field{{}}
+		)
+
+		err := errors.New(msg, fields...)
+		assert.Equal(t, fields, errors.GetFields(err))
+	})
+
+	t.Run("not compatible wrapper error", func(t *testing.T) {
+		t.Parallel()
+
+		var (
+			msg = "some message"
+		)
+		mainErr := errors.New(msg)
+		err := fmt.Errorf("msg: %w", mainErr)
+		assert.Equal(t, mainErr, errors.GetError(err))
+	})
+
+	t.Run("not compatible error", func(t *testing.T) {
+		t.Parallel()
+
+		var (
+			msg = "some message"
+		)
+
+		err := stdErrors.New(msg)
+		willCreateErr := errors.Wrap(err, msg)
+		assert.Equal(t, willCreateErr, errors.GetError(err))
+	})
+}
+
+func TestWrap(t *testing.T) {
+	t.Parallel()
+
+	msg := "some message"
+	cErr := stdErrors.New("cause")
+
+	err := errors.Wrap(cErr, msg)
+	assert.Equal(t, "some message: cause", err.Error())
+}
+
+func TestWrapf(t *testing.T) {
+	t.Parallel()
+
+	format := "some message id: %d"
+	cErr := stdErrors.New("cause")
+
+	err := errors.Wrapf(cErr, format, 10)
+	assert.Equal(t, "some message id: 10: cause", err.Error())
+}
+
+func TestErrorf(t *testing.T) {
+	t.Parallel()
+
+	format := "some message id: %d"
+
+	err := errors.Errorf(format, 10)
+	assert.Equal(t, "some message id: 10", err.Error())
+}
+
+func TestErrorfWithFields(t *testing.T) {
+	t.Parallel()
+
+	format := "some message id: %d"
+	fields := []errors.Field{{}}
+
+	err := errors.ErrorfWithFields(format, []interface{}{10}, fields...)
+	assert.Equal(t, "some message id: 10", err.Error())
+	assert.Equal(t, fields, errors.GetFields(err))
+}
+
+func TestCause(t *testing.T) {
+	t.Parallel()
+
+	t.Run("error with no cause", func(t *testing.T) {
+		err := stdErrors.New("cause")
+
+		assert.Equal(t, err, errors.Cause(err))
+	})
+
+	t.Run("error support causer", func(t *testing.T) {
+		cause := stdErrors.New("cause")
+		err := errors.Wrap(cause, "wrapper")
+
+		assert.Equal(t, cause, errors.Cause(err))
+	})
+
+	t.Run("error support causer", func(t *testing.T) {
+		cause := errors.New("cause")
+		err := errors.Wrap(cause, "wrapper")
+
+		assert.Equal(t, cause, errors.Cause(err))
+	})
+}
+
+func TestError_Format(t *testing.T) {
+	t.Parallel()
+
+	t.Run("format any this with no field", func(t *testing.T) {
+		err := errors.New("some error")
+
+		assert.Equal(t, "some error", fmt.Sprint(err))
+	})
+
+	t.Run("format q", func(t *testing.T) {
+		err := errors.New("some error", errors.String("username", "mrsoftware"))
+
+		assert.Equal(t, "\"some error\": [\"mrsoftware\"]", fmt.Sprintf("%q", err))
+	})
+
+	t.Run("format s", func(t *testing.T) {
+		err := errors.New("some error", errors.String("username", "mrsoftware"))
+
+		assert.Equal(t, "some error: [[username: mrsoftware]]", fmt.Sprintf("%s", err))
+	})
+
+	t.Run("format v", func(t *testing.T) {
+		err := errors.New("some error", errors.String("username", "mrsoftware"))
+
+		assert.Equal(t, "some error: [{Key: username, Value: mrsoftware}]", fmt.Sprintf("%v", err))
+	})
+
+	t.Run("format +v", func(t *testing.T) {
+		err := errors.New("some error", errors.String("username", "mrsoftware"))
+
+		assert.Equal(t, "some error: [{Key: username, Type: String, Value: mrsoftware}]", fmt.Sprintf("%+v", err))
+	})
+
+	t.Run("format #v", func(t *testing.T) {
+		err := errors.New("some error", errors.String("username", "mrsoftware"))
+
+		assert.Equal(t, "some error: []errors.Field{{username: \"mrsoftware\"}}", fmt.Sprintf("%#v", err))
+	})
+}
+
+func TestAddFields(t *testing.T) {
+	t.Parallel()
+
+	t.Run("err is not custom, expect wrap it with custom and add field", func(t *testing.T) {
+		err := stdErrors.New("standard error")
+
+		field := errors.String("code", "value")
+		expect := errors.Wrap(err, err.Error(), field)
+
+		withField := errors.AddFields(err, field)
+
+		assert.Equal(t, expect, withField)
+	})
+}