feat(challenge1): Add functions for counting bytes, lines, words, and…

… characters

challenge1/stats.go

@@ -0,0 +1,33 @@
+
+package main
+
+import (
+	"bufio"
+	"strings"
+	"testing"
+)
+
+func TestCalculateStats(t *testing.T) {
+	cases := []struct {
+		Description string
+		Input       string
+		Want        stats
+	}{
+		{"Empty", "", stats{bytes: 0, words: 0, lines: 0, chars: 0}},
+		{"Single char", "s", stats{bytes: 1, words: 1, lines: 0, chars: 1}},
+		{"Multibyte chars", "s⌘ f", stats{bytes: 6, words: 2, lines: 0, chars: 4}},
+		{"Trailing newline", "this is a sentence\n\nacross multiple\nlines\n", stats{bytes: 42, words: 7, lines: 4, chars: 42}},
+		{"No trailing newline", "this is a sentence\n\nacross multiple\nlines", stats{bytes: 41, words: 7, lines: 3, chars: 41}},
+	}
+
+	for _, test := range cases {
+		t.Run(test.Description, func(t *testing.T) {
+			bufferedString := bufio.NewReader(strings.NewReader(test.Input))
+			got := calculateStats(bufferedString, true, true, true, true)
+
+			if got != test.Want {
+				t.Errorf("got %v, want %v", got, test.Want)
+			}
+		})
+	}
+}