Introduce Helmfile's own filesystem abstraction to correctly unit test some components (#307)

Use abstracted FS

Signed-off-by: Arkaitz Jimenez <arkaitzj@gmail.com>

Signed-off-by: Arkaitz Jimenez <arkaitzj@gmail.com>

pkg/state/helmx.go

@@ -26,16 +26,6 @@ func (st *HelmState) appendHelmXFlags(flags []string, release *ReleaseSpec) ([]s
 	return flags, nil
 }
 
-func fileExistsAt(path string) bool {
-	fileInfo, err := os.Stat(path)
-	return err == nil && fileInfo.Mode().IsRegular()
-}
-
-func directoryExistsAt(path string) bool {
-	fileInfo, err := os.Stat(path)
-	return err == nil && fileInfo.Mode().IsDir()
-}
-
 type Chartify struct {
 	Opts  *chartify.ChartifyOpts
 	Clean func()
@@ -70,7 +60,7 @@ func (st *HelmState) goGetterChart(chart, dir, cacheDir string, force bool) (str
 			return "", fmt.Errorf("Parsing url from dir failed due to error %q.\nContinuing the process assuming this is a regular Helm chart or a local dir.", err.Error())
 		}
 	} else {
-		r := remote.NewRemote(st.logger, "", st.readFile, directoryExistsAt, fileExistsAt)
+		r := remote.NewRemote(st.logger, "", st.fs)
 
 		fetchedDir, err := r.Fetch(chart, cacheDir)
 		if err != nil {
@@ -107,14 +97,14 @@ func (st *HelmState) PrepareChartify(helm helmexec.Interface, release *ReleaseSp
 		dir = filepath.Join(st.basePath, chart)
 	}
 	if stat, _ := os.Stat(dir); stat != nil && stat.IsDir() {
-		if exists, err := st.fileExists(filepath.Join(dir, "Chart.yaml")); err == nil && !exists {
+		if exists, err := st.fs.FileExists(filepath.Join(dir, "Chart.yaml")); err == nil && !exists {
 			shouldRun = true
 		}
 	}
 
 	for _, d := range release.Dependencies {
 		chart := d.Chart
-		if st.directoryExistsAt(chart) {
+		if st.fs.DirectoryExistsAt(chart) {
 			var err error
 
 			// Otherwise helm-dependency-up on the temporary chart generated by chartify ends up errors like: