New function proposal: `files.Walk` (#281)

* Update file.go

Glob function

* returns all the paths of every file inside a directory

* added TrimPrefix function

* avoiding errors when no directory or file is founded

* adapted TrimPrefix to work on pipelines

* tests added for string.TrimPrefix

* strings.TrimSuffix function removed from this PR

* Walk function created

* WalkTest modified to make it compatible with other OS

* first path must be os agnostic too

2 files changed, 36 insertions, 0 deletions

diff --git a/funcs/file.go b/funcs/file.go
index 1f1a30bd..04de4e85 100644
--- a/funcs/file.go
+++ b/funcs/file.go
@@ -55,3 +55,16 @@ func (f *FileFuncs) IsDir(path string) bool {
 func (f *FileFuncs) ReadDir(path string) ([]string, error) {
 	return file.ReadDir(path)
 }
+
+// Walk -
+func (f *FileFuncs) Walk(path string) ([]string, error) {
+	files := make([]string, 0)
+	afero.Walk(f.fs, path, func(subpath string, finfo os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		files = append(files, subpath)
+		return nil
+	})
+	return files, nil
+}
diff --git a/funcs/file_test.go b/funcs/file_test.go
index 2a3ce9a9..56651421 100644
--- a/funcs/file_test.go
+++ b/funcs/file_test.go
@@ -1,6 +1,7 @@
 package funcs
 
 import (
+	"path/filepath"
 	"testing"
 
 	"github.com/spf13/afero"
@@ -30,3 +31,25 @@ func TestFileIsDir(t *testing.T) {
 	assert.True(t, ff.IsDir("/tmp"))
 	assert.False(t, ff.IsDir("/tmp/foo"))
 }
+
+func TestFileWalk(t *testing.T) {
+	fs := afero.NewMemMapFs()
+	ff := &FileFuncs{fs}
+
+	_ = fs.Mkdir("/tmp", 0777)
+	_ = fs.Mkdir("/tmp/bar", 0777)
+	_ = fs.Mkdir("/tmp/bar/baz", 0777)
+	f, _ := fs.Create("/tmp/bar/baz/foo")
+	_, _ = f.Write([]byte("foo"))
+
+	expectedLists := [][]string{{"tmp"}, {"tmp", "bar" }, {"tmp", "bar", "baz"}, {"tmp", "bar", "baz", "foo"}}
+	expectedPaths := make([]string, 0)
+	for _, path := range expectedLists {
+		expectedPaths = append(expectedPaths, string(filepath.Separator) + filepath.Join(path...))
+	}
+
+	actualPaths, err := ff.Walk(string(filepath.Separator) + "tmp")
+
+	assert.NoError(t, err)
+	assert.Equal(t, expectedPaths, actualPaths)
+}