DiceDB#622: Add ECHO command (DiceDB#626)

integration_tests/commands/echo_test.go

@@ -0,0 +1,38 @@
+package commands
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestEcho(t *testing.T) {
+	conn := getLocalConnection()
+	defer conn.Close()
+
+	testCases := []struct {
+		name     string
+		commands []string
+		expected []interface{}
+	}{
+		{
+			name:     "ECHO with invalid number of arguments",
+			commands: []string{"ECHO"},
+			expected: []interface{}{"ERR wrong number of arguments for 'echo' command"},
+		},
+		{
+			name:     "ECHO with one argument",
+			commands: []string{"ECHO \"hello world\""},
+			expected: []interface{}{"hello world"},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			for i, cmd := range tc.commands {
+				result := FireCommand(conn, cmd)
+				assert.Equal(t, tc.expected[i], result, "Value mismatch for cmd %s", cmd)
+			}
+		})
+	}
+}

internal/eval/commands.go

@@ -25,6 +25,12 @@ var (
 		Eval:  evalPING,
 		Arity: -1,
 	}
+	echoCmdMeta = DiceCmdMeta{
+		Name:     "ECHO",
+		Info:     `ECHO returns the string given as argument.`,
+		Eval:     evalECHO,
+		Arity:    1,
+	}
 	authCmdMeta = DiceCmdMeta{
 		Name: "AUTH",
 		Info: `AUTH returns with an encoded "OK" if the user is authenticated.
@@ -785,6 +791,7 @@ var (
 
 func init() {
 	DiceCmds["PING"] = pingCmdMeta
+	DiceCmds["ECHO"] = echoCmdMeta
 	DiceCmds["AUTH"] = authCmdMeta
 	DiceCmds["SET"] = setCmdMeta
 	DiceCmds["GET"] = getCmdMeta

internal/eval/eval.go

@@ -72,6 +72,15 @@ func evalPING(args []string, store *dstore.Store) []byte {
 	return b
 }
 
+// evalECHO returns the argument passed by the user 
+func evalECHO(args []string, store *dstore.Store) []byte {
+	if len(args) != 1 {
+		return diceerrors.NewErrArity("ECHO")
+	}
+
+	return clientio.Encode(args[0], false)
+}
+
 // EvalAUTH returns with an encoded "OK" if the user is authenticated
 // If the user is not authenticated, it returns with an encoded error message
 func EvalAUTH(args []string, c *comm.Client) []byte {

internal/eval/eval_test.go

@@ -41,6 +41,7 @@ func TestEval(t *testing.T) {
 
 	testEvalMSET(t, store)
 	testEvalPING(t, store)
+	testEvalECHO(t, store)
 	testEvalHELLO(t, store)
 	testEvalSET(t, store)
 	testEvalGET(t, store)
@@ -91,6 +92,17 @@ func testEvalPING(t *testing.T, store *dstore.Store) {
 	runEvalTests(t, tests, evalPING, store)
 }
 
+func testEvalECHO(t *testing.T, store *dstore.Store) {
+	tests := map[string]evalTestCase{
+		"nil value":            {input: nil, output: []byte("-ERR wrong number of arguments for 'echo' command\r\n")},
+		"empty args":           {input: []string{}, output: []byte("-ERR wrong number of arguments for 'echo' command\r\n")},
+		"one value":            {input: []string{"HEY"}, output: []byte("$3\r\nHEY\r\n")},
+		"more than one values": {input: []string{"HEY", "HELLO"}, output: []byte("-ERR wrong number of arguments for 'echo' command\r\n")},
+	}
+
+	runEvalTests(t, tests, evalECHO, store)
+}
+
 func testEvalHELLO(t *testing.T, store *dstore.Store) {
 	resp := []interface{}{
 		"proto", 2,