diff --git a/os/gtime/gtime_z_unit_format_test.go b/os/gtime/gtime_z_unit_format_test.go
index 2900a9440..df89b69f5 100644
--- a/os/gtime/gtime_z_unit_format_test.go
+++ b/os/gtime/gtime_z_unit_format_test.go
@@ -92,6 +92,15 @@ func Test_Format(t *testing.T) {
 		}
 
 	})
+	gtest.C(t, func(t *gtest.T) {
+		var ti *gtime.Time = nil
+		t.Assert(ti.Format("Y-m-d h:i:s"), "")
+		t.Assert(ti.FormatNew("Y-m-d h:i:s"), nil)
+		t.Assert(ti.FormatTo("Y-m-d h:i:s"), nil)
+		t.Assert(ti.Layout("Y-m-d h:i:s"), "")
+		t.Assert(ti.LayoutNew("Y-m-d h:i:s"), nil)
+		t.Assert(ti.LayoutTo("Y-m-d h:i:s"), nil)
+	})
 }
 
 func Test_Format_ZeroString(t *testing.T) {
diff --git a/os/gtime/gtime_z_unit_test.go b/os/gtime/gtime_z_unit_test.go
index 7d51f20ed..58351e343 100644
--- a/os/gtime/gtime_z_unit_test.go
+++ b/os/gtime/gtime_z_unit_test.go
@@ -18,10 +18,19 @@ import (
 func Test_SetTimeZone(t *testing.T) {
 	gtest.C(t, func(t *gtest.T) {
 		t.Assert(gtime.SetTimeZone("Asia/Shanghai"), nil)
+		t.AssertNE(gtime.SetTimeZone("testzone"), nil)
 		// t.Assert(time.Local.String(), "Asia/Shanghai")
 	})
 }
 
+func Test_TimestampStr(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		t.AssertGT(len(gtime.TimestampMilliStr()), 0)
+		t.AssertGT(len(gtime.TimestampMicroStr()), 0)
+		t.AssertGT(len(gtime.TimestampNanoStr()), 0)
+	})
+}
+
 func Test_Nanosecond(t *testing.T) {
 	gtest.C(t, func(t *gtest.T) {
 		nanos := gtime.TimestampNano()
@@ -69,6 +78,14 @@ func Test_Datetime(t *testing.T) {
 		}
 		t.Assert(datetime, timeTemp.Time.Format("2006-01-02 15:04:05"))
 	})
+	gtest.C(t, func(t *gtest.T) {
+		timeTemp, err := gtime.StrToTime("")
+		t.Assert(err, nil)
+		t.AssertLT(timeTemp.Unix(), 0)
+		timeTemp, err = gtime.StrToTime("2006-01")
+		t.AssertNE(err, nil)
+		t.Assert(timeTemp, nil)
+	})
 }
 
 func Test_ISO8601(t *testing.T) {
diff --git a/os/gtime/gtime_z_unit_time_test.go b/os/gtime/gtime_z_unit_time_test.go
index 45bd12c71..608c1a10c 100644
--- a/os/gtime/gtime_z_unit_time_test.go
+++ b/os/gtime/gtime_z_unit_time_test.go
@@ -8,6 +8,7 @@ package gtime_test
 
 import (
 	"fmt"
+	"github.com/gogf/gf/v2/internal/json"
 	"testing"
 	"time"
 
@@ -48,6 +49,27 @@ func Test_New(t *testing.T) {
 		timeTemp := gtime.New("2021-2-9 08:01:21")
 		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2021-02-09 08:01:21")
 		t.Assert(timeTemp.Time.Format("2006-01-02 15:04:05"), "2021-02-09 08:01:21")
+
+		timeTemp = gtime.New("2021-02-09 08:01:21", []byte("Y-m-d H:i:s"))
+		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2021-02-09 08:01:21")
+		t.Assert(timeTemp.Time.Format("2006-01-02 15:04:05"), "2021-02-09 08:01:21")
+
+		timeTemp = gtime.New([]byte("2021-02-09 08:01:21"))
+		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2021-02-09 08:01:21")
+		t.Assert(timeTemp.Time.Format("2006-01-02 15:04:05"), "2021-02-09 08:01:21")
+
+		timeTemp = gtime.New([]byte("2021-02-09 08:01:21"), "Y-m-d H:i:s")
+		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2021-02-09 08:01:21")
+		t.Assert(timeTemp.Time.Format("2006-01-02 15:04:05"), "2021-02-09 08:01:21")
+
+		timeTemp = gtime.New([]byte("2021-02-09 08:01:21"), []byte("Y-m-d H:i:s"))
+		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2021-02-09 08:01:21")
+		t.Assert(timeTemp.Time.Format("2006-01-02 15:04:05"), "2021-02-09 08:01:21")
+	})
+	//
+	gtest.C(t, func(t *gtest.T) {
+		t.Assert(gtime.New(gtime.Time{}), nil)
+		t.Assert(gtime.New(&gtime.Time{}), nil)
 	})
 }
 
@@ -124,6 +146,8 @@ func Test_NewFromTimeStamp(t *testing.T) {
 		t.Assert(timeTemp.Format("Y-m-d H:i:s"), "2019-04-05 18:24:06")
 		timeTemp1 := gtime.NewFromTimeStamp(0)
 		t.Assert(timeTemp1.Format("Y-m-d H:i:s"), "0001-01-01 00:00:00")
+		timeTemp2 := gtime.NewFromTimeStamp(155445984)
+		t.Assert(timeTemp2.Format("Y-m-d H:i:s"), "1974-12-05 11:26:24")
 	})
 }
 
@@ -134,6 +158,50 @@ func Test_Time_Second(t *testing.T) {
 	})
 }
 
+func Test_Time_IsZero(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var ti *gtime.Time = nil
+		t.Assert(ti.IsZero(), true)
+	})
+}
+
+func Test_Time_AddStr(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		gt := gtime.New("2018-08-08 08:08:08")
+		gt1, err := gt.AddStr("10T")
+		t.Assert(gt1, nil)
+		t.AssertNE(err, nil)
+	})
+}
+
+func Test_Time_Equal(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var t1 *gtime.Time = nil
+		var t2 = gtime.New()
+		t.Assert(t1.Equal(t2), false)
+		t.Assert(t1.Equal(t1), true)
+		t.Assert(t2.Equal(t1), false)
+	})
+}
+
+func Test_Time_After(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var t1 *gtime.Time = nil
+		var t2 = gtime.New()
+		t.Assert(t1.After(t2), false)
+		t.Assert(t2.After(t1), true)
+	})
+}
+
+func Test_Time_Sub(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var t1 *gtime.Time = nil
+		var t2 = gtime.New()
+		t.Assert(t1.Sub(t2), time.Duration(0))
+		t.Assert(t2.Sub(t1), time.Duration(0))
+	})
+}
+
 func Test_Time_Nanosecond(t *testing.T) {
 	gtest.C(t, func(t *gtest.T) {
 		timeTemp := gtime.Now()
@@ -468,4 +536,15 @@ func Test_DeepCopy(t *testing.T) {
 		u2 := gutil.Copy(u1).(*User)
 		t.Assert(u1, u2)
 	})
+	gtest.C(t, func(t *gtest.T) {
+		var t1 *gtime.Time = nil
+		t.Assert(t1.DeepCopy(), nil)
+	})
+}
+
+func Test_UnmarshalJSON(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		var t1 gtime.Time
+		t.AssertNE(json.Unmarshal([]byte("{}"), &t1), nil)
+	})
 }