diff --git a/internal/integrationtest/compile_4/compile_test.go b/internal/integrationtest/compile_4/compile_test.go
index dc650d5692b..485e2962cd1 100644
--- a/internal/integrationtest/compile_4/compile_test.go
+++ b/internal/integrationtest/compile_4/compile_test.go
@@ -63,6 +63,8 @@ func TestCompileOfProblematicSketches(t *testing.T) {
 	require.NoError(t, err)
 	_, _, err = cli.Run("lib", "install", "CapacitiveSensor@0.5")
 	require.NoError(t, err)
+	_, _, err = cli.Run("lib", "install", "FastLED@3.1.0")
+	require.NoError(t, err)
 
 	// Install custom hardware required for tests
 	customHwDir, err := paths.New("..", "testdata", "user_hardware").Abs()
@@ -114,6 +116,7 @@ func TestCompileOfProblematicSketches(t *testing.T) {
 		{"SketchWithMultilineTemplate", testBuilderSketchWithMultilineTemplate},
 		{"SketchWithFakeFunctionPointer", testBuilderSketchWithFakeFunctionPointer},
 		{"SketchWithMinMaxDefinitions", testBuilderSketchWithMinMaxDefinitions},
+		{"SketchWithFastledsLibrary", testBuilderSketchWithFastledsLibrary},
 	}.Run(t, env, cli)
 }
 
@@ -757,6 +760,22 @@ func testBuilderSketchWithMinMaxDefinitions(t *testing.T, env *integrationtest.E
 	})
 }
 
+func testBuilderSketchWithFastledsLibrary(t *testing.T, env *integrationtest.Environment, cli *integrationtest.ArduinoCLI) {
+	t.Run("Build", func(t *testing.T) {
+		// Build
+		_, err := tryBuild(t, env, cli, "arduino:samd:arduino_zero_native")
+		require.NoError(t, err)
+	})
+
+	t.Run("Preprocess", func(t *testing.T) {
+		// Preprocess
+		sketchPath, preprocessedSketch, err := tryPreprocess(t, env, cli, "arduino:samd:arduino_zero_native")
+		require.NoError(t, err)
+		comparePreprocessGoldenFile(t, sketchPath, preprocessedSketch)
+	})
+}
+
+
 type builderOutput struct {
 	CompilerOut   string `json:"compiler_out"`
 	CompilerErr   string `json:"compiler_err"`
diff --git a/legacy/builder/test/sketch_fastleds/sketch_fastleds.ino b/internal/integrationtest/compile_4/testdata/SketchFastleds/SketchFastleds.ino
similarity index 100%
rename from legacy/builder/test/sketch_fastleds/sketch_fastleds.ino
rename to internal/integrationtest/compile_4/testdata/SketchFastleds/SketchFastleds.ino
diff --git a/internal/integrationtest/compile_4/testdata/SketchFastleds/SketchFastleds.preprocessed.txt b/internal/integrationtest/compile_4/testdata/SketchFastleds/SketchFastleds.preprocessed.txt
new file mode 100644
index 00000000000..e770d0c709b
--- /dev/null
+++ b/internal/integrationtest/compile_4/testdata/SketchFastleds/SketchFastleds.preprocessed.txt
@@ -0,0 +1,37 @@
+#include <Arduino.h>
+#line 1 {{QuoteCppString .sketchMainFile}}
+#include "FastLED.h"
+
+#define DATA_PIN    7
+#define CLK_PIN   6
+#define LED_TYPE    APA102
+#define COLOR_ORDER GRB
+#define NUM_LEDS    79
+CRGB leds[NUM_LEDS];
+
+#define BRIGHTNESS          96
+#define FRAMES_PER_SECOND  120
+#line 12 {{QuoteCppString .sketchMainFile}}
+void setup();
+#line 17 {{QuoteCppString .sketchMainFile}}
+void loop();
+#line 25 {{QuoteCppString .sketchMainFile}}
+void sinelon();
+#line 12 {{QuoteCppString .sketchMainFile}}
+void setup() {
+
+  FastLED.addLeds<LED_TYPE, DATA_PIN, CLK_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
+}
+
+void loop() {
+
+}
+
+typedef void (*SimplePatternList[])();
+//SimplePatternList gPatterns = { rainbow, rainbowWithGlitter, confetti, sinelon, juggle, bpm };
+SimplePatternList gPatterns = {sinelon};
+
+void sinelon()
+{
+}
+
diff --git a/legacy/builder/test/try_build_of_problematic_sketch_test.go b/legacy/builder/test/try_build_of_problematic_sketch_test.go
deleted file mode 100644
index f573cb41977..00000000000
--- a/legacy/builder/test/try_build_of_problematic_sketch_test.go
+++ /dev/null
@@ -1,53 +0,0 @@
-// This file is part of arduino-cli.
-//
-// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
-// Copyright 2015 Matthijs Kooijman
-//
-// This software is released under the GNU General Public License version 3,
-// which covers the main part of arduino-cli.
-// The terms of this license can be found at:
-// https://www.gnu.org/licenses/gpl-3.0.en.html
-//
-// You can be released from the requirements of the above licenses by purchasing
-// a commercial license. Buying such a license is mandatory if you want to
-// modify or otherwise use the software for commercial activities involving the
-// Arduino software without disclosing the source code of your own applications.
-// To purchase a commercial license, send an email to license@arduino.cc.
-
-package test
-
-import (
-	"path/filepath"
-	"testing"
-
-	"github.com/arduino/arduino-cli/arduino/builder/preprocessor"
-	"github.com/arduino/arduino-cli/legacy/builder"
-	"github.com/arduino/arduino-cli/legacy/builder/types"
-	paths "github.com/arduino/go-paths-helper"
-	"github.com/stretchr/testify/require"
-)
-
-// TODO add them in the compile_4
-
-func TestTryBuild036(t *testing.T) {
-	ctx := makeDefaultContext()
-	tryBuildWithContext(t, ctx, "arduino:samd:arduino_zero_native", paths.New("sketch_fastleds", "sketch_fastleds.ino"))
-}
-
-func makeDefaultContext() *types.Context {
-	preprocessor.DebugPreprocessor = true
-	return &types.Context{
-		HardwareDirs:         paths.NewPathList(filepath.Join("..", "hardware"), "downloaded_hardware", "downloaded_board_manager_stuff"),
-		BuiltInToolsDirs:     paths.NewPathList("downloaded_tools"),
-		BuiltInLibrariesDirs: paths.New("downloaded_libraries"),
-		OtherLibrariesDirs:   paths.NewPathList("libraries"),
-	}
-}
-
-func tryBuildWithContext(t *testing.T, ctx *types.Context, fqbn string, sketchLocation *paths.Path) {
-	ctx = prepareBuilderTestContext(t, ctx, sketchLocation, fqbn)
-	defer cleanUpBuilderTestContext(t, ctx)
-
-	err := builder.RunBuilder(ctx)
-	require.NoError(t, err, "Build error for "+sketchLocation.String())
-}