test/fuzz: move fuzz tests into this repo (#5918)

Co-authored-by: Emmanuel T Odeke <emmanuel@orijtech.com>

Closes #5907

- add init-corpus to blockchain reactor
- remove validator-set FromBytes test
now that we have proto, we don't need to test it! bye amino
- simplify mempool test
do we want to test remote ABCI app?
- do not recreate mux on every crash in jsonrpc test
- update p2p pex reactor test
- remove p2p/listener test
the API has changed + I did not understand what it's tested anyway
- update secretconnection test
- add readme and makefile
- list inputs in readme
- add nightly workflow
- remove blockchain fuzz test
EncodeMsg / DecodeMsg no longer exist

test/fuzz/rpc/jsonrpc/server/handler.go

@@ -0,0 +1,44 @@
+package handler
+
+import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+
+	"github.com/tendermint/tendermint/libs/log"
+	rs "github.com/tendermint/tendermint/rpc/jsonrpc/server"
+	types "github.com/tendermint/tendermint/rpc/jsonrpc/types"
+)
+
+var rpcFuncMap = map[string]*rs.RPCFunc{
+	"c": rs.NewRPCFunc(func(s string, i int) (string, int) { return "foo", 200 }, "s,i"),
+}
+var mux *http.ServeMux
+
+func init() {
+	mux := http.NewServeMux()
+	buf := new(bytes.Buffer)
+	lgr := log.NewTMLogger(buf)
+	rs.RegisterRPCFuncs(mux, rpcFuncMap, lgr)
+}
+
+func Fuzz(data []byte) int {
+	req, _ := http.NewRequest("POST", "http://localhost/", bytes.NewReader(data))
+	rec := httptest.NewRecorder()
+	mux.ServeHTTP(rec, req)
+	res := rec.Result()
+	blob, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		panic(err)
+	}
+	if err := res.Body.Close(); err != nil {
+		panic(err)
+	}
+	recv := new(types.RPCResponse)
+	if err := json.Unmarshal(blob, recv); err != nil {
+		panic(err)
+	}
+	return 1
+}