rpc/lib/server: separate out Notifications test

Addressing feedback from @ebuchman

rpc/lib/server/handlers_test.go

@@ -10,16 +10,14 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	rs "github.com/tendermint/tendermint/rpc/lib/server"
 	types "github.com/tendermint/tendermint/rpc/lib/types"
 	"github.com/tendermint/tmlibs/log"
 )
 
-// Ensure that nefarious/unintended inputs to `params`
-// do not crash our RPC handlers.
-// See Issue https://github.com/tendermint/tendermint/issues/708.
-func TestRPCParams(t *testing.T) {
+func testMux() *http.ServeMux {
 	funcMap := map[string]*rs.RPCFunc{
 		"c": rs.NewRPCFunc(func(s string, i int) (string, error) { return "foo", nil }, "s,i"),
 	}
@@ -28,25 +26,31 @@ func TestRPCParams(t *testing.T) {
 	logger := log.NewTMLogger(buf)
 	rs.RegisterRPCFuncs(mux, funcMap, logger)
 
+	return mux
+}
+
+func statusOK(code int) bool { return code >= 200 && code <= 299 }
+
+// Ensure that nefarious/unintended inputs to `params`
+// do not crash our RPC handlers.
+// See Issue https://github.com/tendermint/tendermint/issues/708.
+func TestRPCParams(t *testing.T) {
+	mux := testMux()
 	tests := []struct {
-		payload      string
-		wantErr      string
-		notification bool
+		payload string
+		wantErr string
 	}{
-		{`{"jsonrpc": "2.0"}`, "", true}, // The server SHOULD NOT respond to a notification according to JSONRPC Section 4.1.
-		{`{"jsonrpc": "2.0", "id": "0"}`, "Method not found", false},
-		{`{"jsonrpc": "2.0", "method": "y", "id": "0"}`, "Method not found", false},
-		{`{"jsonrpc": "2.0", "method": "c", "id": "0", "params": null}`, "", false},
-		{`{"method": "c", "id": "0", "params": {}}`, "", false},
-		{`{"method": "c", "id": "0", "params": a}`, "invalid character", false},
-		{`{"method": "c", "id": "0", "params": ["a", 10]}`, "", false},
-		{`{"method": "c", "id": "0", "params": ["a"]}`, "got 1", false},
-		{`{"method": "c", "id": "0", "params": ["a", "b"]}`, "of type int", false},
-		{`{"method": "c", "id": "0", "params": [1, 1]}`, "of type string", false},
+		{`{"jsonrpc": "2.0", "id": "0"}`, "Method not found"},
+		{`{"jsonrpc": "2.0", "method": "y", "id": "0"}`, "Method not found"},
+		{`{"jsonrpc": "2.0", "method": "c", "id": "0", "params": null}`, ""},
+		{`{"method": "c", "id": "0", "params": {}}`, ""},
+		{`{"method": "c", "id": "0", "params": a}`, "invalid character"},
+		{`{"method": "c", "id": "0", "params": ["a", 10]}`, ""},
+		{`{"method": "c", "id": "0", "params": ["a"]}`, "got 1"},
+		{`{"method": "c", "id": "0", "params": ["a", "b"]}`, "of type int"},
+		{`{"method": "c", "id": "0", "params": [1, 1]}`, "of type string"},
 	}
 
-	statusOK := func(code int) bool { return code >= 200 && code <= 299 }
-
 	for i, tt := range tests {
 		req, _ := http.NewRequest("POST", "http://localhost/", strings.NewReader(tt.payload))
 		rec := httptest.NewRecorder()
@@ -60,11 +64,6 @@ func TestRPCParams(t *testing.T) {
 			continue
 		}
 
-		if tt.notification {
-			assert.Equal(t, len(blob), 0, "#%d: a notification SHOULD NOT be responded to by the server", i)
-			continue
-		}
-
 		recv := new(types.RPCResponse)
 		assert.Nil(t, json.Unmarshal(blob, recv), "#%d: expecting successful parsing of an RPCResponse:\nblob: %s", i, blob)
 		assert.NotEqual(t, recv, new(types.RPCResponse), "#%d: not expecting a blank RPCResponse", i)
@@ -78,3 +77,18 @@ func TestRPCParams(t *testing.T) {
 		}
 	}
 }
+
+func TestRPCNotification(t *testing.T) {
+	mux := testMux()
+	body := strings.NewReader(`{"jsonrpc": "2.0"}`)
+	req, _ := http.NewRequest("POST", "http://localhost/", body)
+	rec := httptest.NewRecorder()
+	mux.ServeHTTP(rec, req)
+	res := rec.Result()
+
+	// Always expecting back a JSONRPCResponse
+	require.True(t, statusOK(res.StatusCode), "should always return 2XX")
+	blob, err := ioutil.ReadAll(res.Body)
+	require.Nil(t, err, "reading from the body should not give back an error")
+	require.Equal(t, len(blob), 0, "a notification SHOULD NOT be responded to by the server")
+}