Implement dependencies restore functionallity

plugin.go

@@ -207,6 +207,17 @@ func doHelmInit(p *Plugin) []string {
 
 }
 
+func doDependencyUpdate(chart string) []string {
+	dependencyUpdate := []string{
+		"dependency",
+		"update",
+		chart,
+	}
+
+	return dependencyUpdate
+}
+
+
 // Exec default method
 func (p *Plugin) Exec() error {
 	if p.Config.Debug {
@@ -255,6 +266,12 @@ func (p *Plugin) Exec() error {
 		}
 	}
 
+	if p.Config.UpdateDependencies {
+		if err = runCommand(doDependencyUpdate(p.Config.Chart)); err != nil {
+			return fmt.Errorf("Error updating dependencies: " + err.Error())
+		}
+	}
+
 	setHelmCommand(p)
 
 	if p.Config.Debug {

plugin_test.go

@@ -292,6 +292,16 @@ func TestDetHelmRepoAdd(t *testing.T) {
 	}
 }
 
+func TestDependencyUpdate(t *testing.T) {
+	chart := "./chart"
+	expected := "dependency update ./chart"
+	result := strings.Join(doDependencyUpdate(chart), " ")
+
+	if expected != result {
+		t.Errorf("Helm cannot update repositories - expected %q - got %q", expected, result)
+	}
+}
+
 func TestHelmAddRepositoryError(t *testing.T) {
 	_, err := doHelmRepoAdd("drone-helm=bad://drone-helm.example.com:443/stable")
 	if err == nil {