[unit-testing] Add test for schedule.go (#1938)

* Fix wrong date in release schedule map
	* Fix panic when PercentageForTimeStamp receives time before first bucket & time after last bucket

consensus/reward/schedule.go

@@ -96,7 +96,7 @@ var (
 		mustParse("2025-Feb-28"): numeric.MustNewDecFromStr("0.9941"),
 		mustParse("2025-Mar-31"): numeric.MustNewDecFromStr("0.9961"),
 		mustParse("2025-Apr-30"): numeric.MustNewDecFromStr("0.9980"),
-		mustParse("2025-May-30"): numeric.MustNewDecFromStr("1.0000"),
+		mustParse("2025-May-31"): numeric.MustNewDecFromStr("1.0000"),
 	}
 	sorted = func() []pair {
 		s := []pair{}
@@ -126,8 +126,12 @@ func PercentageForTimeStamp(ts int64) numeric.Dec {
 	i, j := 0, 1
 
 	for range sorted {
-		if i == len(sorted) {
+		if i == (len(sorted) - 1) {
-			bucket = sorted[i-1]
+			if ts < sorted[0].ts {
+				bucket = sorted[0]
+			} else {
+				bucket = sorted[i]
+			}
 			break
 		}
 		if ts >= sorted[i].ts && ts < sorted[j].ts {

consensus/reward/schedule_test.go

@@ -0,0 +1,31 @@
+package reward
+
+import (
+	"testing"
+
+	"github.com/harmony-one/harmony/numeric"
+)
+
+func TestPercentageForTimeStamp(t *testing.T) {
+	testCases := []struct {
+		time     string
+		expected string
+	}{
+		{"2019-Jan-01", "0.2429"},
+		{"2019-May-31", "0.2429"},
+		{"2021-Nov-30", "0.8561"},
+		{"2023-Apr-29", "0.9488"},
+		{"2023-Apr-30", "0.9507"},
+		{"2025-May-31", "1.0000"},
+		{"2026-Jan-01", "1.0000"},
+	}
+
+	for _, tc := range testCases {
+		result := PercentageForTimeStamp(mustParse(tc.time))
+		expect := numeric.MustNewDecFromStr(tc.expected)
+		if !result.Equal(expect) {
+			t.Errorf("Time: %s, Chosen bucket percent: %s, Expected: %s",
+				tc.time, result, expect)
+		}
+	}
+}