add functions/vendor files

vendor/github.com/dghubble/go-twitter/twitter/errors_test.go

@@ -0,0 +1,48 @@
+package twitter
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var errAPI = APIError{
+	Errors: []ErrorDetail{
+		ErrorDetail{Message: "Status is a duplicate", Code: 187},
+	},
+}
+var errHTTP = fmt.Errorf("unknown host")
+
+func TestAPIError_Error(t *testing.T) {
+	err := APIError{}
+	if assert.Error(t, err) {
+		assert.Equal(t, "", err.Error())
+	}
+	if assert.Error(t, errAPI) {
+		assert.Equal(t, "twitter: 187 Status is a duplicate", errAPI.Error())
+	}
+}
+
+func TestAPIError_Empty(t *testing.T) {
+	err := APIError{}
+	assert.True(t, err.Empty())
+	assert.False(t, errAPI.Empty())
+}
+
+func TestRelevantError(t *testing.T) {
+	cases := []struct {
+		httpError error
+		apiError  APIError
+		expected  error
+	}{
+		{nil, APIError{}, nil},
+		{nil, errAPI, errAPI},
+		{errHTTP, APIError{}, errHTTP},
+		{errHTTP, errAPI, errHTTP},
+	}
+	for _, c := range cases {
+		err := relevantError(c.httpError, c.apiError)
+		assert.Equal(t, c.expected, err)
+	}
+}