docs: add examples for API

examples/worldcup/main_test.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConvertTimeToSeconds(t *testing.T) {
+	testData := []struct {
+		timeStr string
+		seconds int
+	}{
+		{"00:00", 0},
+		{"00:01", 1},
+		{"01:00", 60},
+		{"01:01", 61},
+		{"00:01:02", 62},
+		{"01:02:03", 3723},
+	}
+
+	for _, td := range testData {
+		seconds, err := convertTimeToSeconds(td.timeStr)
+		assert.Nil(t, err)
+		assert.Equal(t, td.seconds, seconds)
+	}
+}
+
+func TestMain(t *testing.T) {
+	main()
+}