test: add a simple test suite

phonetic_letters.go

@@ -12,27 +12,24 @@ func main() {
 	flag.BoolVar(&all, "all", false, "reveal the code words of all the letters in the English alphabet.")
 	flag.Parse()
 
-	var input string
-
 	if all {
-		input = fullAlphabet()
+		fmt.Print(phoneticLetters(fullAlphabet()))
 	} else {
-		args := flag.Args()
-		for i := range args {
-			input = input + args[i]
-		}
+		fmt.Print(phoneticLetters(flag.Args()...))
 	}
-
-	fmt.Print(phoneticLetters(input))
 }
 
 // phoneticLetters returns a string of all the code words for the given set of letters.
-func phoneticLetters(letters string) string {
-	letters = strings.ToLower(letters)
+func phoneticLetters(input... string) string {
+	var characters string
+
+	for i := range input {
+		characters = characters + strings.ToLower(input[i])
+	}
 
 	b := strings.Builder{}
 
-	for _, r := range letters {
+	for _, r := range characters {
 		switch r {
 		case 'a':
 			b.WriteString("A - Alpha\n")

phonetic_letters_test.go

@@ -0,0 +1,75 @@
+package main
+
+import "testing"
+
+func TestPhoneticLetters(t *testing.T) {
+	t.Log("This is the test suite for phonetic-letters")
+	t.Run("Test the application with one string", testWithOneString)
+	t.Run("Test the application with two strings", testWithTwoStrings)
+	t.Run("Test the application with numbers and symbols", testWithNumbersAndSymbols)
+}
+
+func testWithOneString(t *testing.T) {
+	input := "phonetic"
+
+	got := phoneticLetters(input)
+
+	want := `P - Papa
+H - Hotel
+O - Oscar
+N - November
+E - Echo
+T - Tango
+I - India
+C - Charlie
+`
+
+	if want != got {
+		t.Errorf("Unexpected result returned from phoneticLetters(); want %s, got %s", want, got)
+	}
+}
+
+func testWithTwoStrings(t *testing.T) {
+	input := []string{"three", "coins"}
+
+	got := phoneticLetters(input...)
+
+	want := `T - Tango
+H - Hotel
+R - Romeo
+E - Echo
+E - Echo
+C - Charlie
+O - Oscar
+I - India
+N - November
+S - Sierra
+`
+
+	if want != got {
+		t.Errorf("Unexpected result returned from phoneticLetters(); want %s, got %s", want, got)
+	}
+}
+
+func testWithNumbersAndSymbols(t *testing.T) {
+	input := "Hello, 8 Worlds!"
+
+	got := phoneticLetters(input)
+
+	want := `H - Hotel
+E - Echo
+L - Lima
+L - Lima
+O - Oscar
+W - Whiskey
+O - Oscar
+R - Romeo
+L - Lima
+D - Delta
+S - Sierra
+`
+
+	if want != got {
+		t.Errorf("Unexpected result returned from phoneticLetters(); want %s, got %s", want, got)
+	}
+}