diff --git a/apier/v1/apier.go b/apier/v1/apier.go
index 6941ed54b..a34028aa2 100644
--- a/apier/v1/apier.go
+++ b/apier/v1/apier.go
@@ -877,7 +877,8 @@ func verifyFormat(tStr string) bool {
 // checkDefaultTiming will check the tStr if it's of the the default timings ( the same as in TPReader )
 // and will compute it properly
 func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
-	startTime := time.Now().Format("15:04:05")
+	currentTime := time.Now()
+	fmtTime := currentTime.Format("15:04:05")
 	switch tStr {
 	case utils.MetaEveryMinute:
 		return &engine.RITiming{
@@ -886,7 +887,7 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			Months:    utils.Months{},
 			MonthDays: utils.MonthDays{},
 			WeekDays:  utils.WeekDays{},
-			StartTime: utils.ConcatenatedKey(utils.Meta, utils.Meta, strconv.Itoa(time.Now().Second())),
+			StartTime: utils.ConcatenatedKey(utils.Meta, utils.Meta, strconv.Itoa(currentTime.Second())),
 			EndTime:   "",
 		}, true
 	case utils.MetaHourly:
@@ -896,7 +897,7 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			Months:    utils.Months{},
 			MonthDays: utils.MonthDays{},
 			WeekDays:  utils.WeekDays{},
-			StartTime: utils.ConcatenatedKey(utils.Meta, strconv.Itoa(time.Now().Minute()), strconv.Itoa(time.Now().Second())),
+			StartTime: utils.ConcatenatedKey(utils.Meta, strconv.Itoa(currentTime.Minute()), strconv.Itoa(currentTime.Second())),
 			EndTime:   "",
 		}, true
 	case utils.MetaDaily:
@@ -906,7 +907,7 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			Months:    utils.Months{},
 			MonthDays: utils.MonthDays{},
 			WeekDays:  utils.WeekDays{},
-			StartTime: startTime,
+			StartTime: fmtTime,
 			EndTime:   ""}, true
 	case utils.MetaWeekly:
 		return &engine.RITiming{
@@ -914,8 +915,8 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			Years:     utils.Years{},
 			Months:    utils.Months{},
 			MonthDays: utils.MonthDays{},
-			WeekDays:  utils.WeekDays{time.Now().Weekday()},
-			StartTime: startTime,
+			WeekDays:  utils.WeekDays{currentTime.Weekday()},
+			StartTime: fmtTime,
 			EndTime:   "",
 		}, true
 	case utils.MetaMonthly:
@@ -923,9 +924,9 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			ID:        utils.MetaMonthly,
 			Years:     utils.Years{},
 			Months:    utils.Months{},
-			MonthDays: utils.MonthDays{time.Now().Day()},
+			MonthDays: utils.MonthDays{currentTime.Day()},
 			WeekDays:  utils.WeekDays{},
-			StartTime: startTime,
+			StartTime: fmtTime,
 			EndTime:   "",
 		}, true
 	case utils.MetaMonthlyEstimated:
@@ -933,9 +934,9 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			ID:        utils.MetaMonthlyEstimated,
 			Years:     utils.Years{},
 			Months:    utils.Months{},
-			MonthDays: utils.MonthDays{time.Now().Day()},
+			MonthDays: utils.MonthDays{currentTime.Day()},
 			WeekDays:  utils.WeekDays{},
-			StartTime: startTime,
+			StartTime: fmtTime,
 			EndTime:   "",
 		}, true
 	case utils.MetaMonthEnd:
@@ -945,17 +946,17 @@ func checkDefaultTiming(tStr string) (rTm *engine.RITiming, isDefault bool) {
 			Months:    utils.Months{},
 			MonthDays: utils.MonthDays{-1},
 			WeekDays:  utils.WeekDays{},
-			StartTime: startTime,
+			StartTime: fmtTime,
 			EndTime:   "",
 		}, true
 	case utils.MetaYearly:
 		return &engine.RITiming{
 			ID:        utils.MetaYearly,
 			Years:     utils.Years{},
-			Months:    utils.Months{time.Now().Month()},
-			MonthDays: utils.MonthDays{time.Now().Day()},
+			Months:    utils.Months{currentTime.Month()},
+			MonthDays: utils.MonthDays{currentTime.Day()},
 			WeekDays:  utils.WeekDays{},
-			StartTime: startTime,
+			StartTime: fmtTime,
 			EndTime:   "",
 		}, true
 	default:
diff --git a/engine/rateinterval.go b/engine/rateinterval.go
index 14e468c78..a1ed6b29a 100644
--- a/engine/rateinterval.go
+++ b/engine/rateinterval.go
@@ -70,9 +70,15 @@ func (rit *RITiming) CronString() string {
 		} else {
 			hour, min, sec = "*", "*", "*"
 		}
-		hour = strings.TrimPrefix(hour, "0")
-		min = strings.TrimPrefix(min, "0")
-		sec = strings.TrimPrefix(sec, "0")
+		if len(hour) > 1 {
+			hour = strings.TrimPrefix(hour, "0")
+		}
+		if len(min) > 1 {
+			min = strings.TrimPrefix(min, "0")
+		}
+		if len(sec) > 1 {
+			sec = strings.TrimPrefix(sec, "0")
+		}
 	}
 	if len(rit.MonthDays) == 0 {
 		monthday = "*"
diff --git a/engine/rateinterval_test.go b/engine/rateinterval_test.go
index 8402e6ab2..1e8a952a8 100644
--- a/engine/rateinterval_test.go
+++ b/engine/rateinterval_test.go
@@ -296,73 +296,138 @@ func TestRateStrigyfy(t *testing.T) {
 	}
 }
 
-func TestRateIntervalCronAll(t *testing.T) {
-	rit := &RITiming{
-		Years:     utils.Years{2012},
-		Months:    utils.Months{time.February},
-		MonthDays: utils.MonthDays{1},
-		WeekDays:  []time.Weekday{time.Sunday},
-		StartTime: "14:30:00",
+func TestRateInterval_CronStringTT(t *testing.T) {
+	testCases := []struct {
+		name     string
+		ri       *RITiming
+		wantCron string
+	}{
+		{
+			name: "SingleYearMonthMonthDayWeekDay",
+			ri: &RITiming{
+				Years:     utils.Years{2012},
+				Months:    utils.Months{time.February},
+				MonthDays: utils.MonthDays{1},
+				WeekDays:  []time.Weekday{time.Sunday},
+				StartTime: "14:30:00",
+			},
+			wantCron: "0 30 14 1 2 0 2012",
+		},
+		{
+			name: "MultipleYearsMonthsMonthsDaysWeekDays",
+			ri: &RITiming{
+				Years:     utils.Years{2012, 2014},
+				Months:    utils.Months{time.February, time.January},
+				MonthDays: utils.MonthDays{15, 16},
+				WeekDays:  []time.Weekday{time.Sunday, time.Monday},
+				StartTime: "14:30:00",
+			},
+			wantCron: "0 30 14 15,16 2,1 0,1 2012,2014",
+		},
+		{
+			name: "WildcardStartTime",
+			ri: &RITiming{
+				StartTime: "*:30:00",
+			},
+			wantCron: "0 30 * * * * *",
+		},
+		{
+			name:     "AllFieldsEmpty",
+			ri:       &RITiming{},
+			wantCron: "* * * * * * *",
+		},
+		{
+			name: "EveryMinute",
+			ri: &RITiming{
+				StartTime: utils.MetaEveryMinute,
+			},
+			wantCron: "0 * * * * * *",
+		},
+		{
+			name: "Hourly",
+			ri: &RITiming{
+				StartTime: utils.MetaHourly,
+			},
+			wantCron: "0 0 * * * * *",
+		},
+		{
+			name: "SingleDigit0Hour",
+			ri: &RITiming{
+				StartTime: "0:49:25",
+			},
+			wantCron: "25 49 0 * * * *",
+		},
+		{
+			name: "SingleDigit0Minute",
+			ri: &RITiming{
+				StartTime: "*:0:49",
+			},
+			wantCron: "49 0 * * * * *",
+		},
+		{
+			name: "SingleDigit0Second",
+			ri: &RITiming{
+				StartTime: "*:49:0",
+			},
+			wantCron: "0 49 * * * * *",
+		},
+		{
+			name: "DoubleDigit0Hour",
+			ri: &RITiming{
+				StartTime: "00:49:25",
+			},
+			wantCron: "25 49 0 * * * *",
+		},
+		{
+			name: "DoubleDigit0Minute",
+			ri: &RITiming{
+				StartTime: "*:00:49",
+			},
+			wantCron: "49 0 * * * * *",
+		},
+		{
+			name: "DoubleDigit0Second",
+			ri: &RITiming{
+				StartTime: "*:49:00",
+			},
+			wantCron: "0 49 * * * * *",
+		},
+		{
+			name: "InvalidStartTimeFormat",
+			ri: &RITiming{
+				StartTime: "223000",
+			},
+			wantCron: "* * * * * * *",
+		},
+		{
+			name: "LastDayOfMonthSpecifiedAsNegative",
+			ri: &RITiming{
+				StartTime: "223000",
+				MonthDays: utils.MonthDays{-1},
+			},
+			wantCron: "* * * L * * *",
+		},
+		{
+			name: "PatternWithZeros",
+			ri: &RITiming{
+				Years:     utils.Years{2020},
+				Months:    utils.Months{1},
+				MonthDays: utils.MonthDays{0},
+				WeekDays:  []time.Weekday{time.Monday},
+				StartTime: "00:00:00",
+			},
+			wantCron: "0 0 0 0 1 1 2020",
+		},
 	}
-	expected := "0 30 14 1 2 0 2012"
-	cron := rit.CronString()
-	if cron != expected {
-		t.Errorf("Expected %s was %s", expected, cron)
-	}
-}
 
-func TestRateIntervalCronMultiple(t *testing.T) {
-	rit := &RITiming{
-		Years:     utils.Years{2012, 2014},
-		Months:    utils.Months{time.February, time.January},
-		MonthDays: utils.MonthDays{15, 16},
-		WeekDays:  []time.Weekday{time.Sunday, time.Monday},
-		StartTime: "14:30:00",
-	}
-	expected := "0 30 14 15,16 2,1 0,1 2012,2014"
-	cron := rit.CronString()
-
-	if cron != expected {
-		t.Errorf("Expected %s was %s", expected, cron)
-	}
-}
-
-func TestRateIntervalCronStar(t *testing.T) {
-	rit := &RITiming{
-		StartTime: "*:30:00",
-	}
-	expected := "0 30 * * * * *"
-	cron := rit.CronString()
-
-	if cron != expected {
-		t.Errorf("Expected %s was %s", expected, cron)
-	}
-}
-
-func TestRateIntervalCronEmpty(t *testing.T) {
-	rit := &RITiming{}
-	expected := "* * * * * * *"
-	cron := rit.CronString()
-
-	if cron != expected {
-		t.Errorf("Expected %s was %s", expected, cron)
-	}
-}
-
-func TestRITimingCronEveryX(t *testing.T) {
-	rit := &RITiming{
-		StartTime: utils.MetaEveryMinute,
-	}
-	eCronStr := "0 * * * * * *"
-	if cronStr := rit.CronString(); cronStr != eCronStr {
-		t.Errorf("Expecting: <%s>, received: <%s>", eCronStr, cronStr)
-	}
-	rit = &RITiming{
-		StartTime: utils.MetaHourly,
-	}
-	eCronStr = "0 0 * * * * *"
-	if cronStr := rit.CronString(); cronStr != eCronStr {
-		t.Errorf("Expecting: <%s>, received: <%s>", eCronStr, cronStr)
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			got := tc.ri.CronString()
+			if got != tc.wantCron {
+				t.Errorf("RITiming=%s\nCronString()=%q, want %q", utils.ToJSON(tc.ri), got, tc.wantCron)
+			}
+		})
 	}
 }
 
@@ -576,27 +641,6 @@ func BenchmarkRateIntervalContainsDate(b *testing.B) {
 	}
 }
 
-func TestRateIntervalCronStringDefault(t *testing.T) {
-	rit := &RITiming{
-		StartTime: "223000",
-	}
-	cron := rit.CronString()
-	if !reflect.DeepEqual(cron, "* * * * * * *") {
-		t.Errorf("\nExpecting: <* * * * * * *>,\n Received: <%+v>", cron)
-	}
-}
-
-func TestRateIntervalCronStringMonthDayNegative(t *testing.T) {
-	rit := &RITiming{
-		StartTime: "223000",
-		MonthDays: utils.MonthDays{-1},
-	}
-	cron := rit.CronString()
-	if !reflect.DeepEqual(cron, "* * * L * * *") {
-		t.Errorf("\nExpecting: <* * * L * * *>,\n Received: <%+v>", cron)
-	}
-}
-
 func TestRateIntervalIsActiveAt(t *testing.T) {
 	rit := &RITiming{}
 	cronActive := rit.IsActive()
@@ -620,7 +664,7 @@ func TestRateIntervalFieldAsInterfaceError(t *testing.T) {
 		Value: 2.2,
 	}
 	_, err := rateTest.FieldAsInterface([]string{"FALSE"})
-	if err == nil && err.Error() != "unsupported field prefix: <FALSE>" {
+	if err == nil || err.Error() != "unsupported field prefix: <FALSE>" {
 		t.Errorf("\nExpecting: <unsupported field prefix: <FALSE>>,\n Received: <%+v>", err)
 	}
 }
@@ -629,7 +673,7 @@ func TestRateIntervalFieldAsInterfaceError2(t *testing.T) {
 	rateTest := &RGRate{}
 	_, err := rateTest.FieldAsInterface([]string{"value1", "value2"})
 
-	if err == nil && err != utils.ErrNotFound {
+	if err != utils.ErrNotFound {
 		t.Errorf("\nExpecting: <NOT_FOUND>,\n Received: <%+v>", err)
 	}
 }
diff --git a/engine/tpreader.go b/engine/tpreader.go
index e5f157103..606261f14 100644
--- a/engine/tpreader.go
+++ b/engine/tpreader.go
@@ -2398,13 +2398,14 @@ func (tpr *TpReader) addDefaultTimings() {
 		StartTime: utils.MetaASAP,
 		EndTime:   "",
 	}
+	currentTime := time.Now()
 	tpr.timings[utils.MetaEveryMinute] = &utils.TPTiming{
 		ID:        utils.MetaEveryMinute,
 		Years:     utils.Years{},
 		Months:    utils.Months{},
 		MonthDays: utils.MonthDays{},
 		WeekDays:  utils.WeekDays{},
-		StartTime: utils.ConcatenatedKey(utils.Meta, utils.Meta, strconv.Itoa(time.Now().Second())),
+		StartTime: utils.ConcatenatedKey(utils.Meta, utils.Meta, strconv.Itoa(currentTime.Second())),
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaHourly] = &utils.TPTiming{
@@ -2413,17 +2414,17 @@ func (tpr *TpReader) addDefaultTimings() {
 		Months:    utils.Months{},
 		MonthDays: utils.MonthDays{},
 		WeekDays:  utils.WeekDays{},
-		StartTime: utils.ConcatenatedKey(utils.Meta, strconv.Itoa(time.Now().Minute()), strconv.Itoa(time.Now().Second())),
+		StartTime: utils.ConcatenatedKey(utils.Meta, strconv.Itoa(currentTime.Minute()), strconv.Itoa(currentTime.Second())),
 		EndTime:   "",
 	}
-	startTime := time.Now().Format("15:04:05")
+	fmtTime := currentTime.Format("15:04:05")
 	tpr.timings[utils.MetaDaily] = &utils.TPTiming{
 		ID:        utils.MetaDaily,
 		Years:     utils.Years{},
 		Months:    utils.Months{},
 		MonthDays: utils.MonthDays{},
 		WeekDays:  utils.WeekDays{},
-		StartTime: startTime,
+		StartTime: fmtTime,
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaWeekly] = &utils.TPTiming{
@@ -2431,26 +2432,26 @@ func (tpr *TpReader) addDefaultTimings() {
 		Years:     utils.Years{},
 		Months:    utils.Months{},
 		MonthDays: utils.MonthDays{},
-		WeekDays:  utils.WeekDays{time.Now().Weekday()},
-		StartTime: startTime,
+		WeekDays:  utils.WeekDays{currentTime.Weekday()},
+		StartTime: fmtTime,
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaMonthly] = &utils.TPTiming{
 		ID:        utils.MetaMonthly,
 		Years:     utils.Years{},
 		Months:    utils.Months{},
-		MonthDays: utils.MonthDays{time.Now().Day()},
+		MonthDays: utils.MonthDays{currentTime.Day()},
 		WeekDays:  utils.WeekDays{},
-		StartTime: startTime,
+		StartTime: fmtTime,
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaMonthlyEstimated] = &utils.TPTiming{
 		ID:        utils.MetaMonthlyEstimated,
 		Years:     utils.Years{},
 		Months:    utils.Months{},
-		MonthDays: utils.MonthDays{time.Now().Day()},
+		MonthDays: utils.MonthDays{currentTime.Day()},
 		WeekDays:  utils.WeekDays{},
-		StartTime: startTime,
+		StartTime: fmtTime,
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaMonthEnd] = &utils.TPTiming{
@@ -2459,16 +2460,16 @@ func (tpr *TpReader) addDefaultTimings() {
 		Months:    utils.Months{},
 		MonthDays: utils.MonthDays{-1},
 		WeekDays:  utils.WeekDays{},
-		StartTime: startTime,
+		StartTime: fmtTime,
 		EndTime:   "",
 	}
 	tpr.timings[utils.MetaYearly] = &utils.TPTiming{
 		ID:        utils.MetaYearly,
 		Years:     utils.Years{},
-		Months:    utils.Months{time.Now().Month()},
-		MonthDays: utils.MonthDays{time.Now().Day()},
+		Months:    utils.Months{currentTime.Month()},
+		MonthDays: utils.MonthDays{currentTime.Day()},
 		WeekDays:  utils.WeekDays{},
-		StartTime: startTime,
+		StartTime: fmtTime,
 		EndTime:   "",
 	}