Add ZPopMin and ZPopMax (#853)

* Add ZPopMin and ZPopMax

commands.go

@@ -206,6 +206,8 @@ type Cmdable interface {
 	ZLexCount(key, min, max string) *IntCmd
 	ZIncrBy(key string, increment float64, member string) *FloatCmd
 	ZInterStore(destination string, store ZStore, keys ...string) *IntCmd
+	ZPopMax(key string, count ...int64) *ZSliceCmd
+	ZPopMin(key string, count ...int64) *ZSliceCmd
 	ZRange(key string, start, stop int64) *StringSliceCmd
 	ZRangeWithScores(key string, start, stop int64) *ZSliceCmd
 	ZRangeByScore(key string, opt ZRangeBy) *StringSliceCmd
@@ -1694,6 +1696,46 @@ func (c *cmdable) ZInterStore(destination string, store ZStore, keys ...string)
 	return cmd
 }
 
+func (c *cmdable) ZPopMax(key string, count ...int64) *ZSliceCmd {
+	args := []interface{}{
+		"zpopmax",
+		key,
+	}
+
+	switch len(count) {
+	case 0:
+		break
+	case 1:
+		args = append(args, count[0])
+	default:
+		panic("too many arguments")
+	}
+
+	cmd := NewZSliceCmd(args...)
+	c.process(cmd)
+	return cmd
+}
+
+func (c *cmdable) ZPopMin(key string, count ...int64) *ZSliceCmd {
+	args := []interface{}{
+		"zpopmin",
+		key,
+	}
+
+	switch len(count) {
+	case 0:
+		break
+	case 1:
+		args = append(args, count[0])
+	default:
+		panic("too many arguments")
+	}
+
+	cmd := NewZSliceCmd(args...)
+	c.process(cmd)
+	return cmd
+}
+
 func (c *cmdable) zRange(key string, start, stop int64, withScores bool) *StringSliceCmd {
 	args := []interface{}{
 		"zrange",

commands_test.go

@@ -2518,6 +2518,135 @@ var _ = Describe("Commands", func() {
 			}}))
 		})
 
+		It("should ZPopMax", func() {
+			err := client.ZAdd("zset", redis.Z{
+				Score:  1,
+				Member: "one",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  2,
+				Member: "two",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  3,
+				Member: "three",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			members, err := client.ZPopMax("zset").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  3,
+				Member: "three",
+			}}))
+
+			// adding back 3
+			err = client.ZAdd("zset", redis.Z{
+				Score:  3,
+				Member: "three",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			members, err = client.ZPopMax("zset", 2).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  3,
+				Member: "three",
+			}, {
+				Score:  2,
+				Member: "two",
+			}}))
+
+			// adding back 2 & 3
+			err = client.ZAdd("zset", redis.Z{
+				Score:  3,
+				Member: "three",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  2,
+				Member: "two",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			members, err = client.ZPopMax("zset", 10).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  3,
+				Member: "three",
+			}, {
+				Score:  2,
+				Member: "two",
+			}, {
+				Score:  1,
+				Member: "one",
+			}}))
+		})
+
+		It("should ZPopMin", func() {
+			err := client.ZAdd("zset", redis.Z{
+				Score:  1,
+				Member: "one",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  2,
+				Member: "two",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  3,
+				Member: "three",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			members, err := client.ZPopMin("zset").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  1,
+				Member: "one",
+			}}))
+
+			// adding back 1
+			err = client.ZAdd("zset", redis.Z{
+				Score:  1,
+				Member: "one",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			members, err = client.ZPopMin("zset", 2).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  1,
+				Member: "one",
+			}, {
+				Score:  2,
+				Member: "two",
+			}}))
+
+			// adding back 1 & 2
+			err = client.ZAdd("zset", redis.Z{
+				Score:  1,
+				Member: "one",
+			}).Err()
+			Expect(err).NotTo(HaveOccurred())
+			err = client.ZAdd("zset", redis.Z{
+				Score:  2,
+				Member: "two",
+			}).Err()
+			members, err = client.ZPopMin("zset", 10).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(members).To(Equal([]redis.Z{{
+				Score:  1,
+				Member: "one",
+			}, {
+				Score:  2,
+				Member: "two",
+			}, {
+				Score:  3,
+				Member: "three",
+			}}))
+		})
+
 		It("should ZRange", func() {
 			err := client.ZAdd("zset", redis.Z{Score: 1, Member: "one"}).Err()
 			Expect(err).NotTo(HaveOccurred())