Show an IRC listener user what their session sends from other clients (closes #179)

The relay dropped every PRIVMSG, NOTICE, JOIN, PART, NICK, QUIT, TOPIC,
MODE and KICK sent under the connection's own nick, so an IRC listener
connection never saw what its session did from another client. The
relay now drops nothing by nick. Instead, the service methods that fan
out a user's own command take the client whose queue to skip: the IRC
listener passes its own client, which has already written the echo, and
the HTTP API passes 0. Channel messages and PARTs now also go to the
sender's own session, so the HTTP handler no longer queues the
channel-message echo itself, SendChannelMessage no longer returns the
message's row ID, and neoirc-cli ignores the PART event for its own
part, which it has already shown.

Model: opus-5-5

internal/cli/app_internal_test.go

@@ -3,7 +3,9 @@ package cli
 import (
 	"testing"
 
+	"github.com/gdamore/tcell/v2"
 	api "sneak.berlin/go/neoirc/internal/cli/api"
+	"sneak.berlin/go/neoirc/pkg/irc"
 )
 
 func TestMemberPrefix(t *testing.T) {
@@ -49,3 +51,66 @@ func TestMemberPrefix(t *testing.T) {
 		})
 	}
 }
+
+// TestPartEvent checks that a PART event adds a line to the
+// channel's buffer and marks it unread, except for the
+// user's own part, which cmdPart has already shown.
+func TestPartEvent(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		from       string
+		wantLines  int
+		wantUnread int
+	}{
+		{name: "own part", from: "alice", wantLines: 0, wantUnread: 0},
+		{name: "other member", from: "bob", wantLines: 1, wantUnread: 1},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+
+			app := &App{ui: NewUI(), nick: "alice"}
+			runUI(t, app.ui)
+
+			app.handleServerMessage(&api.Message{
+				Command: irc.CmdPart, From: test.from, To: "#chan",
+			})
+
+			var lines, unread int
+
+			app.ui.app.QueueUpdate(func() {
+				buf := app.ui.getOrCreateBuffer("#chan")
+				lines = len(buf.Lines)
+				unread = buf.Unread
+			})
+
+			if lines != test.wantLines || unread != test.wantUnread {
+				t.Fatalf("got %d lines and %d unread, want %d and %d",
+					lines, unread, test.wantLines, test.wantUnread)
+			}
+		})
+	}
+}
+
+// runUI runs ui on a simulated screen until the test ends.
+func runUI(t *testing.T, ui *UI) {
+	t.Helper()
+
+	ui.app.SetScreen(tcell.NewSimulationScreen(""))
+
+	done := make(chan error)
+
+	go func() { done <- ui.Run() }()
+
+	t.Cleanup(func() {
+		ui.Stop()
+
+		err := <-done
+		if err != nil {
+			t.Errorf("run ui: %v", err)
+		}
+	})
+}