Add convenience function for detecting main sketch files in a path

Author: per1234

Diff for: project/sketch/sketch.go

@@ -20,6 +20,8 @@ See: https://arduino.github.io/arduino-cli/latest/sketch-specification/
 package sketch
 
 import (
+	"fmt"
+
 	"github.com/arduino/arduino-cli/arduino/globals"
 	"github.com/arduino/go-paths-helper"
 )
@@ -31,6 +33,30 @@ func HasMainFileValidExtension(filePath *paths.Path) bool {
 	return hasMainFileValidExtension
 }
 
+// ContainsMainSketchFile checks whether the provided path contains a file with valid main sketch file extension.
+func ContainsMainSketchFile(searchPath *paths.Path) bool {
+	if searchPath.NotExist() {
+		panic(fmt.Sprintf("Error: provided path %s does not exist.", searchPath))
+	}
+	if searchPath.IsNotDir() {
+		panic(fmt.Sprintf("Error: provided path %s is not a directory.", searchPath))
+	}
+
+	directoryListing, err := searchPath.ReadDir()
+	if err != nil {
+		panic(err)
+	}
+
+	directoryListing.FilterOutDirs()
+	for _, potentialHeaderFile := range directoryListing {
+		if HasMainFileValidExtension(potentialHeaderFile) {
+			return true
+		}
+	}
+
+	return false
+}
+
 // HasSupportedExtension returns whether the file at the given path has any of the file extensions supported for source/header files of a sketch.
 func HasSupportedExtension(filePath *paths.Path) bool {
 	_, hasAdditionalFileValidExtensions := globals.AdditionalFileValidExtensions[filePath.Ext()]

Diff for: project/sketch/sketch_test.go

@@ -16,17 +16,30 @@
 package sketch
 
 import (
+	"os"
 	"testing"
 
 	"github.com/arduino/go-paths-helper"
 	"github.com/stretchr/testify/assert"
 )
 
+var testDataPath *paths.Path
+
+func init() {
+	workingDirectory, _ := os.Getwd()
+	testDataPath = paths.New(workingDirectory, "testdata")
+}
+
 func TestHasMainFileValidExtension(t *testing.T) {
 	assert.True(t, HasMainFileValidExtension(paths.New("/foo/bar.ino")))
 	assert.False(t, HasMainFileValidExtension(paths.New("/foo/bar.h")))
 }
 
+func TestContainsMainSketchFile(t *testing.T) {
+	assert.True(t, ContainsMainSketchFile(testDataPath.Join("Valid")))
+	assert.False(t, ContainsMainSketchFile(testDataPath.Join("ContainsNoMainSketchFile")))
+}
+
 func TestHasSupportedExtension(t *testing.T) {
 	assert.True(t, HasSupportedExtension(paths.New("/foo/bar.ino")))
 	assert.True(t, HasSupportedExtension(paths.New("/foo/bar.h")))

Diff for: project/sketch/testdata/ContainsNoMainSketchFile/foo.bar

@@ -0,0 +1,2 @@
+void setup() {}
+void loop() {}