GETEXwith EX with big integer reports an error (DiceDB#576)

* fixed getex big integer expire issue

* added unit test for GETEX command

* updated unit testcase for GETEX command

* updated maxExDuration logic for getex

internal/eval/eval.go

@@ -2068,7 +2068,7 @@ func evalGETEX(args []string, store *dstore.Store) []byte {
 			if err != nil {
 				return diceerrors.NewErrWithMessage(diceerrors.IntOrOutOfRangeErr)
 			}
-			if exDuration <= 0 {
+			if exDuration <= 0 || exDuration > maxExDuration {
 				return diceerrors.NewErrExpireTime("GETEX")
 			}
 

internal/eval/eval_test.go

@@ -66,6 +66,7 @@ func TestEval(t *testing.T) {
 	testEvalHLEN(t, store)
 	testEvalSELECT(t, store)
 	testEvalLLEN(t, store)
+	testEvalGETEX(t, store)
 }
 
 func testEvalPING(t *testing.T, store *dstore.Store) {
@@ -123,6 +124,37 @@ func testEvalSET(t *testing.T, store *dstore.Store) {
 	runEvalTests(t, tests, evalSET, store)
 }
 
+func testEvalGETEX(t *testing.T, store *dstore.Store) {
+	tests := map[string]evalTestCase{
+
+		"key val pair and valid EX": {
+			setup: func() {
+				key := "foo"
+				value := "bar"
+				obj := &object.Obj{
+					Value: value,
+				}
+				store.Put(key, obj)
+			},
+			input:  []string{"foo", Ex, "10"},
+			output: clientio.Encode("bar", false),
+		},
+		"key val pair and invalid EX": {
+			setup: func() {
+				key := "foo"
+				value := "bar"
+				obj := &object.Obj{
+					Value: value,
+				}
+				store.Put(key, obj)
+			},
+			input:  []string{"foo", Ex, "10000000000000000"},
+			output: []byte("-ERR invalid expire time in 'getex' command\r\n")},
+	}
+
+	runEvalTests(t, tests, evalGETEX, store)
+}
+
 func testEvalMSET(t *testing.T, store *dstore.Store) {
 	tests := map[string]evalTestCase{
 		"nil value":         {input: nil, output: []byte("-ERR wrong number of arguments for 'mset' command\r\n")},