Add TestReadFile

main.go

@@ -117,21 +117,6 @@ func openURL(rawurl string) error {
 	return nil
 }
 
-func readFile(fp string) (string, error) {
-	f, err := os.Open(fp)
-	if err != nil {
-		return "", err
-	}
-	defer f.Close()
-
-	bs, err := ioutil.ReadAll(f)
-	if err != nil {
-		return "", err
-	}
-
-	return string(bs), nil
-}
-
 func loadToken() (string, error) {
 	configFilePath, err := getConfigFilePath()
 	if err != nil {
@@ -177,6 +162,21 @@ func getToken() (string, error) {
 	return token, nil
 }
 
+func readFile(fp string) (string, error) {
+	f, err := os.Open(fp)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	bs, err := ioutil.ReadAll(f)
+	if err != nil {
+		return "", err
+	}
+
+	return string(bs), nil
+}
+
 func saveToken(token, configFilePath string) error {
 	if err := os.MkdirAll(filepath.Dir(configFilePath), 0700); err != nil {
 		return err

main_test.go

@@ -8,6 +8,26 @@ import (
 	"testing"
 )
 
+func TestReadFile(t *testing.T) {
+	testFilePath := "test.tmp"
+	testContent := "test"
+	if err := ioutil.WriteFile(testFilePath, []byte(testContent), 0600); err != nil {
+		t.Fatalf("should not be nil: %v", err)
+	}
+	defer func() {
+		if err := os.Remove(testFilePath); err != nil {
+			t.Fatalf("should not be fail: %v", err)
+		}
+	}()
+	content, err := readFile(testFilePath)
+	if err != nil {
+		t.Fatalf("should not be nil: %v", err)
+	}
+	if content != testContent {
+		t.Fatalf("want %q but %q", testContent, content)
+	}
+}
+
 func TestSaveToken(t *testing.T) {
 	token := "abcde"
 	fp := "/tmp/gistup/token"