feat: implement WAIT command as no-op (#420)

* feat: implement WAIT command as no-op

* add small int test

---------

Co-authored-by: Harmen <alicebob@lijzij.de>

Author: aroullet

README.md

@@ -57,6 +57,7 @@ Implemented commands:
    - TTL
    - TYPE
    - UNLINK
+   - WAIT -- no-op
  - Transactions (complete)
    - DISCARD
    - EXEC
@@ -305,7 +306,6 @@ Commands which will probably not be implemented:
  - Key
     - ~~MIGRATE~~
     - ~~OBJECT~~
-    - ~~WAIT~~
  - Scripting
     - ~~FCALL / FCALL_RO *~~
     - ~~FUNCTION *~~

cmd_generic.go

@@ -56,6 +56,7 @@ func commandsGeneric(m *Miniredis) {
 	m.srv.Register("SCAN", m.cmdScan, server.ReadOnlyOption())
 	// SORT
 	m.srv.Register("UNLINK", m.cmdDel)
+	m.srv.Register("WAIT", m.cmdWait)
 }
 
 type expireOpts struct {
@@ -773,3 +774,26 @@ func (m *Miniredis) cmdCopy(c *server.Peer, cmd string, args []string) {
 		c.WriteInt(1)
 	})
 }
+
+// WAIT
+func (m *Miniredis) cmdWait(c *server.Peer, cmd string, args []string) {
+	if !m.isValidCMD(c, cmd, args, exactly(2)) {
+		return
+	}
+	nReplicas, err := strconv.Atoi(args[0])
+	if err != nil || nReplicas < 0 {
+		c.WriteError(msgInvalidInt)
+		return
+	}
+	timeout, err := strconv.Atoi(args[1])
+	if err != nil {
+		c.WriteError(msgInvalidInt)
+		return
+	}
+	if timeout < 0 {
+		c.WriteError(msgTimeoutNegative)
+		return
+	}
+	// WAIT always returns 0 when called on a standalone instance
+	c.WriteInt(0)
+}

cmd_generic_test.go

@@ -990,3 +990,27 @@ func TestCopy(t *testing.T) {
 		)
 	})
 }
+
+func TestWait(t *testing.T) {
+	_, c := runWithClient(t)
+
+	t.Run("success", func(t *testing.T) {
+		must0(t, c, "WAIT", "2", "100")
+		must0(t, c, "WAIT", "1", "0")
+	})
+
+	t.Run("errors", func(t *testing.T) {
+		mustDo(t, c, "WAIT",
+			proto.Error(errWrongNumber("wait")),
+		)
+		mustDo(t, c, "WAIT", "2",
+			proto.Error(errWrongNumber("wait")),
+		)
+		mustDo(t, c, "WAIT", "2", "bar",
+			proto.Error(msgInvalidInt),
+		)
+		mustDo(t, c, "WAIT", "foo", "100",
+			proto.Error(msgInvalidInt),
+		)
+	})
+}

cmd_scripting_test.go

@@ -469,6 +469,11 @@ func TestCmdEvalResponse(t *testing.T) {
 		"EVAL", "return redis.call('HMGET','mkey', 'bad', 'key')", "0",
 		proto.Array(proto.Nil, proto.Nil),
 	)
+
+	mustDo(t, c,
+		"EVAL", "return redis.call('WAIT', '2', '100')", "0",
+		proto.Int(0),
+	)
 }
 
 func TestCmdEvalAuth(t *testing.T) {

integration/server_test.go

@@ -55,6 +55,19 @@ func TestServer(t *testing.T) {
 		c.Error("wrong number of arguments", "MEMORY", "USAGE")
 		c.Error("syntax error", "MEMORY", "USAGE", "too", "many")
 	})
+
+	testRaw(t, func(c *client) {
+		c.DoLoosely("WAIT", "1", "1")
+
+		// Failure cases
+		c.Error("wrong number", "WAIT", "1")
+		c.Error("wrong number", "WAIT", "1", "2", "3")
+		c.Error("wrong number", "WAIT")
+		c.Error("not an integer", "WAIT", "foo", "0")
+		c.Error("not an integer", "WAIT", "1", "foo")
+		// c.Error("out of range", "WAIT", "-1", "0") // something weird going on
+		c.Error("timeout is negative", "WAIT", "11", "-12")
+	})
 }
 
 func TestServerTLS(t *testing.T) {