Added test for arduino/Arduino#5186

Signed-off-by: Cristian Maglie <c.maglie@arduino.cc>

Author: cmaglie

src/arduino.cc/builder/test/sketch13/sketch13.ino

@@ -0,0 +1,16 @@
+/*
+This sketch tests if the sketch folder il fully copied into the tmp folder,
+so it allows to include files contained in subfolders.
+
+See: https://github.com/arduino/Arduino/issues/5186
+*/
+
+#include "test/test123.h"
+
+void setup() {
+    Serial.begin(9600);
+    Serial.print(testvar);
+}
+
+void loop() {
+}

src/arduino.cc/builder/test/sketch13/test/test123.h

@@ -0,0 +1,2 @@
+
+int testvar = 100;

src/arduino.cc/builder/test/try_build_of_problematic_sketch_test.go

@@ -31,11 +31,12 @@
 package test
 
 import (
-	"arduino.cc/builder"
-	"arduino.cc/builder/types"
 	"os"
 	"path/filepath"
 	"testing"
+
+	"arduino.cc/builder"
+	"arduino.cc/builder/types"
 )
 
 func TestTryBuild001(t *testing.T) {
@@ -205,6 +206,10 @@ func TestTryBuild039(t *testing.T) {
 	tryBuildWithContext(t, ctx, "sketch12", "sketch12.ino")
 }
 
+func TestTryBuild040(t *testing.T) {
+	tryBuild(t, "sketch13", "sketch13.ino")
+}
+
 func makeDefaultContext(t *testing.T) *types.Context {
 	DownloadCoresAndToolsAndLibraries(t)