Added ErrAppNotRunning

pkg/visor/rpc.go

@@ -190,11 +190,7 @@ func (r *RPC) StartApp(name *string, _ *struct{}) error {
 
 // StopApp stops App with provided name.
 func (r *RPC) StopApp(name *string, _ *struct{}) error {
-	err := r.node.StopApp(*name)
-	if err == ErrUnknownApp {
-		err = errors.New("app is either non-existent, or is already stopped")
-	}
-	return err
+	return r.node.StopApp(*name)
 }
 
 // SetAutoStartIn is input for SetAutoStart.

pkg/visor/rpc_test.go

@@ -1,7 +1,6 @@
 package visor
 
 import (
-	"errors"
 	"fmt"
 	"net/http"
 	"os"
@@ -125,7 +124,7 @@ func TestStartStopApp(t *testing.T) {
 
 	err = rpc.StopApp(&unknownApp, nil)
 	require.Error(t, err)
-	assert.Equal(t, errors.New("app is either non-existent, or is already stopped"), err)
+	assert.Equal(t, ErrAppNotRunning, err)
 
 	require.NoError(t, rpc.StopApp(&app, nil))
 	time.Sleep(100 * time.Millisecond)

pkg/visor/visor.go

@@ -50,6 +50,9 @@ const (
 // ErrUnknownApp represents lookup error for App related calls.
 var ErrUnknownApp = errors.New("unknown app")
 
+// ErrAppNotRunning occurs when an app is attempted to be stopped when it was not running.
+var ErrAppNotRunning = errors.New("app is not running")
+
 // Version is the node version.
 const Version = "0.0.1"
 
@@ -532,7 +535,7 @@ func (node *Node) StopApp(appName string) error {
 	node.startedMu.Unlock()
 
 	if bind == nil {
-		return ErrUnknownApp
+		return ErrAppNotRunning
 	}
 
 	return node.stopApp(appName, bind)