lab 03 updated, issue fixed

03_letters/marchitect/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+var out io.Writer = os.Stdout
+
+func letters(s string) map[rune]int {
+	m := make(map[rune]int)
+	// keep a list of what characters exist in the string s
+	chars := ""
+	for _, c := range s {
+		if !strings.ContainsAny(chars, string(c)) {
+			numberOfc := strings.Count(s, string(c))
+			m[c] = numberOfc
+			chars += string(c)
+		}
+	}
+	return m
+}
+
+func sortLetters(m map[rune]int) []string {
+	result := make([]string, 0)
+	keys := make([]int, 0)
+	for k := range m {
+		keys = append(keys, int(k))
+	}
+	sort.Ints(keys)
+	for _, k := range keys {
+		unquoted, _ := strconv.Unquote(strconv.QuoteRune(rune(k)))
+		result = append(result, unquoted+":"+strconv.Itoa(m[rune(k)]))
+	}
+	return result
+}
+
+func main() {
+	fmt.Fprintln(out, strings.Join(sortLetters(letters("aba")), "\n"))
+}

03_letters/marchitect/main_test.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"bytes"
+	"reflect"
+	"strconv"
+	"testing"
+)
+
+// this testing function aims to test two functions letters() and sortLetters() from main, together
+func Test_letters_and_sortLetters(t *testing.T) {
+	tables := []struct {
+		nameOfTestcase string
+		input          string
+		output         []string
+	}{
+		{"normal test 1", "test", []string{"e:1", "s:1", "t:2"}},
+		{"normal test 2", "$Bfs`BY", []string{"$:1", "B:2", "Y:1", "`:1", "f:1", "s:1"}},
+		{"empty input", "", []string{}},
+		{"Mandarin Characters Hello", "你好", []string{"你:1", "好:1"}},
+		{"normal test 3", "Brain drained", []string{" :1", "B:1", "a:2", "d:2", "e:1", "i:2", "n:2", "r:2"}},
+	}
+	for _, table := range tables {
+		expected := sortLetters(letters(table.input))
+		actual := table.output
+		// reference: https://yourbasic.org/golang/compare-slices/
+		if !reflect.DeepEqual(actual, expected) {
+			t.Errorf("Unexpected output from test %s, expected = %s, actual = %s", table.nameOfTestcase, expected, actual)
+		}
+	}
+}
+
+func Test_main(t *testing.T) {
+	var buf bytes.Buffer
+	out = &buf
+
+	main()
+
+	expected := strconv.Quote(`a:2
+b:1
+`)
+	actual := strconv.Quote(buf.String())
+
+	if expected != actual {
+		t.Errorf("Unexpected output in main(), expected = %v, actual = %v", expected, actual)
+	}
+}