Implement Lab3 Letter frequency

03_letters/sirigithub/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+var out io.Writer = os.Stdout
+
+func letters(s string) map[rune]int {
+	runeFreq := make(map[rune]int)
+	for _, r := range s {
+		runeFreq[r]++
+	}
+	return runeFreq
+}
+
+// sortLetters returns a sorted slice of strings with elements {key}:{val} from the input map m
+func sortLetters(m map[rune]int) []string {
+	sortedStrings := make([]string, 0, len(m))
+	for key, value := range m {
+		frequency := string(key) + ":" + strconv.Itoa(value)
+		sortedStrings = append(sortedStrings, frequency)
+	}
+	sort.Strings(sortedStrings)
+	return sortedStrings
+}
+
+func main() {
+	fmt.Fprintln(out, strings.Join(sortLetters(letters("aba")), "\n"))
+}

03_letters/sirigithub/main_test.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLetterFrequency(t *testing.T) {
+	tests := []struct {
+		description string
+		input       string
+		expected    []string
+	}{
+		{description: "Simple string", input: "thisisasimplestring",
+			expected: []string{"a:1", "e:1", "g:1", "h:1", "i:4", "l:1", "m:1", "n:1", "p:1", "r:1", "s:4", "t:2"}},
+
+		{description: "String with spaces", input: "   223  ", expected: []string{" :5", "2:2", "3:1"}},
+
+		{description: "Empty String", input: "", expected: []string{}},
+
+		{description: "German Umlauts", input: "äö߀’üüüöäßß", expected: []string{"ß:3", "ä:2", "ö:2", "ü:3", "’:1", "€:1"}},
+
+		{description: "String with Back slashes", input: "a\\c\\b", expected: []string{"\\:2", "a:1", "b:1", "c:1"}},
+
+		{description: "String with Emojis", input: "😄🐷🙈🐷🏃😄", expected: []string{"🏃:1", "🐷:2", "😄:2", "🙈:1"}},
+	}
+
+	for _, test := range tests {
+		actual := sortLetters(letters(test.input))
+		expected := test.expected
+		t.Run(test.description, func(t *testing.T) {
+			assert.Equal(t, actual, expected, "actual %v but expected %v", actual, expected)
+		})
+	}
+}
+
+func TestMainOutput(t *testing.T) {
+	var buf bytes.Buffer
+	out = &buf
+	main()
+	expected := "a:2\nb:1\n"
+	actual := buf.String()
+
+	if expected != actual {
+		t.Errorf("Unexpected output in main(). Expected = %v Actual = %v", expected, actual)
+	}
+}