Add check for missing library examples

Author: per1234

check/checkconfigurations/checkconfigurations.go

@@ -1016,6 +1016,21 @@ var configurations = []Type{
 		ErrorModes:      []checkmode.Type{checkmode.Default},
 		CheckFunction:   checkfunctions.IncorrectLibrarySrcFolderNameCase,
 	},
+	{
+		ProjectType:     projecttype.Library,
+		Category:        "structure",
+		Subcategory:     "",
+		ID:              "",
+		Brief:           "no examples",
+		Description:     "",
+		MessageTemplate: "No example sketches found. Please provide examples. See: https://arduino.github.io/arduino-cli/latest/library-specification/#library-examples",
+		DisableModes:    nil,
+		EnableModes:     []checkmode.Type{checkmode.Default},
+		InfoModes:       nil,
+		WarningModes:    []checkmode.Type{checkmode.Default},
+		ErrorModes:      nil,
+		CheckFunction:   checkfunctions.MissingExamples,
+	},
 	{
 		ProjectType:     projecttype.Library,
 		Category:        "structure",

check/checkfunctions/library.go

@@ -1084,6 +1084,28 @@ func IncorrectLibrarySrcFolderNameCase() (result checkresult.Type, output string
 	return checkresult.Pass, ""
 }
 
+// MissingExamples checks whether the library is missing examples.
+func MissingExamples() (result checkresult.Type, output string) {
+	for _, examplesFolderName := range library.ExamplesFolderSupportedNames() {
+		examplesPath := checkdata.ProjectPath().Join(examplesFolderName)
+		exists, err := examplesPath.IsDirCheck()
+		if err != nil {
+			panic(err)
+		}
+		if exists {
+			directoryListing, _ := examplesPath.ReadDirRecursive()
+			directoryListing.FilterDirs()
+			for _, potentialExamplePath := range directoryListing {
+				if sketch.ContainsMainSketchFile(potentialExamplePath) {
+					return checkresult.Pass, ""
+				}
+			}
+		}
+	}
+
+	return checkresult.Fail, ""
+}
+
 // MisspelledExamplesFolderName checks for incorrectly spelled `examples` folder name.
 func MisspelledExamplesFolderName() (result checkresult.Type, output string) {
 	directoryListing, err := checkdata.ProjectPath().ReadDir()

check/checkfunctions/library_test.go

@@ -342,6 +342,16 @@ func TestIncorrectLibrarySrcFolderNameCase(t *testing.T) {
 	checkLibraryCheckFunction(IncorrectLibrarySrcFolderNameCase, testTables, t)
 }
 
+func TestMissingExamples(t *testing.T) {
+	testTables := []libraryCheckFunctionTestTable{
+		{"Has examples", "ExamplesFolder", checkresult.Pass, ""},
+		{`Has examples (in "example" folder)`, "ExampleFolder", checkresult.Pass, ""},
+		{"No examples", "NoExamples", checkresult.Fail, ""},
+	}
+
+	checkLibraryCheckFunction(MissingExamples, testTables, t)
+}
+
 func TestMisspelledExamplesFolderName(t *testing.T) {
 	testTables := []libraryCheckFunctionTestTable{
 		{"Correctly spelled", "ExamplesFolder", checkresult.Pass, ""},

check/checkfunctions/testdata/libraries/ExampleFolder/example/Example/Example.ino

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

check/checkfunctions/testdata/libraries/ExampleFolder/library.properties

@@ -0,0 +1,9 @@
+name=ExampleFolder
+version=1.0.0
+author=Cristian Maglie <[email protected]>, Pippo Pluto <[email protected]>
+maintainer=Cristian Maglie <[email protected]>
+sentence=A library that makes coding a web server a breeze.
+paragraph=Supports HTTP1.1 and you can do GET and POST.
+category=Communication
+url=http://example.com/
+architectures=avr