Move sliceContains to new package pkg/sliceutil (#1333)

* Move sliceContains to new package pkg/sliceutil

* Test sliceutil

pkg/config/reader.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/golangci/golangci-lint/pkg/fsutils"
 	"github.com/golangci/golangci-lint/pkg/logutils"
+	"github.com/golangci/golangci-lint/pkg/sliceutil"
 )
 
 type FileReader struct {
@@ -183,7 +184,7 @@ func (r *FileReader) setupConfigFileSearch() {
 	// find home directory for global config
 	if home, err := homedir.Dir(); err != nil {
 		r.log.Warnf("Can't get user's home directory: %s", err.Error())
-	} else if !sliceContains(configSearchPaths, home) {
+	} else if !sliceutil.Contains(configSearchPaths, home) {
 		configSearchPaths = append(configSearchPaths, home)
 	}
 
@@ -194,15 +195,6 @@ func (r *FileReader) setupConfigFileSearch() {
 	}
 }
 
-func sliceContains(slice []string, value string) bool {
-	for _, v := range slice {
-		if v == value {
-			return true
-		}
-	}
-	return false
-}
-
 var errConfigDisabled = errors.New("config is disabled by --no-config")
 
 func (r *FileReader) parseConfigOption() (string, error) {

pkg/sliceutil/sliceutil.go

@@ -0,0 +1,17 @@
+package sliceutil
+
+// IndexOf get the index of the given value in the given string slice,
+// or -1 if not found.
+func IndexOf(slice []string, value string) int {
+	for i, v := range slice {
+		if v == value {
+			return i
+		}
+	}
+	return -1
+}
+
+// Contains check if a string slice contains a value.
+func Contains(slice []string, value string) bool {
+	return IndexOf(slice, value) != -1
+}

pkg/sliceutil/sliceutil_test.go

@@ -0,0 +1,17 @@
+package sliceutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContains(t *testing.T) {
+	assert.True(t, Contains([]string{"val1", "val2", "val3"}, "val2"))
+	assert.False(t, Contains([]string{"val1", "val2", "val3"}, "val4"))
+}
+
+func TestIndexOf(t *testing.T) {
+	assert.Equal(t, 1, IndexOf([]string{"val1", "val2", "val3"}, "val2"))
+	assert.Equal(t, -1, IndexOf([]string{"val1", "val2", "val3"}, "val4"))
+}