Give each IRC listener test its own database (closes #129)

Each test environment in internal/ircserver named its shared in-memory
database after the test. A repeat run of a test in the same process
could open the database that an earlier run's server was still
holding, and start on that run's users. The database now gets a random
name, and a new test checks that two environments open at once do not
share one.

The database close and the server stop are now registered as soon as
each is opened, so a setup that fails part-way still closes its
database.

Model: opus-5-5

internal/db/queries.go

@@ -204,21 +204,42 @@ func (database *Database) GetSessionByToken(
 		)
 	}
 
+	_ = database.UpdateLastSeen(ctx, sessionID, clientID)
+
+	return sessionID, clientID, nick, nil
+}
+
+// UpdateLastSeen sets last_seen to now on a session and on
+// one of its clients, so that the idle cleanup keeps them.
+func (database *Database) UpdateLastSeen(
+	ctx context.Context,
+	sessionID, clientID int64,
+) error {
 	now := time.Now()
 
-	_, _ = database.conn.ExecContext(
+	_, err := database.conn.ExecContext(
 		ctx,
 		"UPDATE sessions SET last_seen = ? WHERE id = ?",
 		now, sessionID,
 	)
+	if err != nil {
+		return fmt.Errorf(
+			"update session last_seen: %w", err,
+		)
+	}
 
-	_, _ = database.conn.ExecContext(
+	_, err = database.conn.ExecContext(
 		ctx,
 		"UPDATE clients SET last_seen = ? WHERE id = ?",
 		now, clientID,
 	)
+	if err != nil {
+		return fmt.Errorf(
+			"update client last_seen: %w", err,
+		)
+	}
 
-	return sessionID, clientID, nick, nil
+	return nil
 }
 
 // GetSessionByNick returns session id for a given nick.

internal/ircserver/conn.go

@@ -368,6 +368,17 @@ func (c *Conn) handleMessage(
 		return
 	}
 
+	// Every command is activity, so the idle cleanup must not
+	// remove this user.
+	err := c.database.UpdateLastSeen(
+		ctx, c.sessionID, c.clientID,
+	)
+	if err != nil {
+		c.log.Error(
+			"failed to update last_seen", "error", err,
+		)
+	}
+
 	handler, ok := c.commands[msg.Command]
 	if !ok {
 		c.sendNumeric(

internal/ircserver/server_test.go

@@ -2,6 +2,7 @@ package ircserver_test
 
 import (
 	"bufio"
+	"crypto/rand"
 	"database/sql"
 	"fmt"
 	"log/slog"
@@ -69,9 +70,11 @@ func newTestEnvWithConfig(
 ) *testEnv {
 	t.Helper()
 
+	// A random name, so that no other test environment, not
+	// even an earlier run of the same test, can share it.
 	dsn := fmt.Sprintf(
 		"file:%s?mode=memory&cache=shared&_journal_mode=WAL",
-		t.Name(),
+		rand.Text(),
 	)
 
 	conn, err := sql.Open("sqlite", dsn)
@@ -79,6 +82,13 @@ func newTestEnvWithConfig(
 		t.Fatalf("open db: %v", err)
 	}
 
+	t.Cleanup(func() {
+		err := conn.Close()
+		if err != nil {
+			t.Logf("close db: %v", err)
+		}
+	})
+
 	conn.SetMaxOpenConns(1)
 
 	_, err = conn.ExecContext(
@@ -123,14 +133,9 @@ func newTestEnvWithConfig(
 		t.Fatalf("start irc server: %v", err)
 	}
 
-	t.Cleanup(func() {
-		srv.Stop()
-
-		err := conn.Close()
-		if err != nil {
-			t.Logf("close db: %v", err)
-		}
-	})
+	// Cleanups run last registered first, so the server stops
+	// before its database is closed.
+	t.Cleanup(srv.Stop)
 
 	return &testEnv{
 		database: database,
@@ -342,6 +347,20 @@ func TestRegistration(t *testing.T) {
 	assertContains(t, lines, " 001 ", "RPL_WELCOME")
 }
 
+// TestEachTestEnvHasItsOwnDatabase checks that a test
+// environment starts on an empty database while another one
+// is still open.
+func TestEachTestEnvHasItsOwnDatabase(t *testing.T) {
+	t.Parallel()
+
+	first := newTestEnv(t)
+	first.dial(t).register("samenick")
+
+	second := newTestEnv(t)
+	lines := second.dial(t).register("samenick")
+	assertContains(t, lines, " 001 ", "RPL_WELCOME")
+}
+
 func TestWelcomeContainsNick(t *testing.T) {
 	t.Parallel()
 
@@ -369,6 +388,39 @@ func TestPingPong(t *testing.T) {
 	assertContains(t, lines, "PONG", "PONG response")
 }
 
+// TestIdleCleanupKeepsActiveUser checks that a user who
+// sends commands is kept by the idle cleanup, and a user who
+// sends nothing is not.
+func TestIdleCleanupKeepsActiveUser(t *testing.T) {
+	t.Parallel()
+
+	const idleTimeout = 500 * time.Millisecond
+
+	env := newTestEnv(t)
+
+	active := env.dial(t)
+	active.register("active")
+
+	idle := env.dial(t)
+	idle.register("idle")
+
+	time.Sleep(idleTimeout)
+	active.sendAndExpect("PING :still here", "PONG")
+
+	// The idle cleanup in internal/handlers removes exactly
+	// the users this returns.
+	stale, err := env.database.GetStaleOrphanSessions(
+		t.Context(), time.Now().Add(-idleTimeout),
+	)
+	if err != nil {
+		t.Fatalf("get stale sessions: %v", err)
+	}
+
+	if len(stale) != 1 || stale[0].Nick != "idle" {
+		t.Errorf("cleanup removes %v, want only idle", stale)
+	}
+}
+
 func TestJoinChannel(t *testing.T) {
 	t.Parallel()