diff --git a/go.mod b/go.mod
index 6966a3c..6084911 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.13
 
 require (
 	github.com/go-redis/redis/v7 v7.0.0-beta.4
-	github.com/google/go-cmp v0.3.1
+	github.com/google/go-cmp v0.4.0
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/pelletier/go-toml v1.6.0 // indirect
 	github.com/rs/xid v1.2.1
diff --git a/go.sum b/go.sum
index a409284..2bc98ac 100644
--- a/go.sum
+++ b/go.sum
@@ -39,8 +39,8 @@ github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
-github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
-github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1 h1:EGx4pi6eqNxGaHF6qqu48+N2wcFQ5qg5FXgOdqsJ5d8=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
@@ -185,6 +185,8 @@ golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGm
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190328211700-ab21143f2384/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
diff --git a/internal/rdb/inspect_test.go b/internal/rdb/inspect_test.go
index 71589a6..8674427 100644
--- a/internal/rdb/inspect_test.go
+++ b/internal/rdb/inspect_test.go
@@ -10,49 +10,12 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	h "github.com/hibiken/asynq/internal/asynqtest"
 	"github.com/hibiken/asynq/internal/base"
 	"github.com/rs/xid"
 )
 
-// TODO(hibiken): Replace this with cmpopts.EquateApproxTime once it becomes availalble.
-// https://github.com/google/go-cmp/issues/166
-//
-// EquateApproxTime returns a Comparer options that
-// determine two time.Time values to be equal if they
-// are within the given time interval of one another.
-// Note that if both times have a monotonic clock reading,
-// the monotonic time difference will be used.
-//
-// The zero time is treated specially: it is only considered
-// equal to another zero time value.
-//
-// It will panic if margin is negative.
-func EquateApproxTime(margin time.Duration) cmp.Option {
-	if margin < 0 {
-		panic("negative duration in EquateApproxTime")
-	}
-	return cmp.FilterValues(func(x, y time.Time) bool {
-		return !x.IsZero() && !y.IsZero()
-	}, cmp.Comparer(timeApproximator{margin}.compare))
-}
-
-type timeApproximator struct {
-	margin time.Duration
-}
-
-func (a timeApproximator) compare(x, y time.Time) bool {
-	// Avoid subtracting times to avoid overflow when the
-	// difference is larger than the largest representible duration.
-	if x.After(y) {
-		// Ensure x is always before y
-		x, y = y, x
-	}
-	// We're within the margin if x+margin >= y.
-	// Note: time.Time doesn't have AfterOrEqual method hence the negation.
-	return !x.Add(a.margin).Before(y)
-}
-
 func TestCurrentStats(t *testing.T) {
 	r := setup(t)
 	m1 := h.NewTaskMessage("send_email", map[string]interface{}{"subject": "hello"})
@@ -535,7 +498,7 @@ func TestListDead(t *testing.T) {
 	}
 }
 
-var timeCmpOpt = EquateApproxTime(time.Second)
+var timeCmpOpt = cmpopts.EquateApproxTime(time.Second)
 
 func TestEnqueueDeadTask(t *testing.T) {
 	r := setup(t)