Test that losing the state directory ends every login session (part of #256)

A pixa started on an empty state directory must refuse a session cookie
from before, and a login on it must open the generator page. With the
count of logouts, the new pixa starts from 0 again and accepts the old
cookie, so this test fails until the count is replaced.

Model: opus-5-5

internal/server/logout_internal_test.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"net/url"
+	"path/filepath"
 	"regexp"
 	"strings"
 	"testing"
@@ -230,3 +231,39 @@ func TestLogoutOutlastsRestart(t *testing.T) {
 			"still opens the generator page")
 	}
 }
+
+// TestLostStateDirectoryEndsEveryLoginSession verifies that a pixa started on
+// an empty state directory, as pixad is after a restart that lost its state
+// directory, refuses a session cookie from before, and that a login on it
+// opens the generator page.
+func TestLostStateDirectoryEndsEveryLoginSession(t *testing.T) {
+	t.Parallel()
+
+	s := newTestServer(t)
+
+	before := logIn(t, s)
+	if !opensGeneratorPage(t, s, before) {
+		t.Fatal("logging in did not open the generator page")
+	}
+
+	emptyStateDir := *s.config
+	emptyStateDir.StateDir = t.TempDir()
+	emptyStateDir.DBURL = "file:" +
+		filepath.Join(emptyStateDir.StateDir, "state.sqlite3")
+
+	restarted := startPixa(t, &emptyStateDir)
+
+	opens := opensGeneratorPage(t, restarted, before)
+	t.Logf("on an empty state directory, the cookie from before opens the "+
+		"generator page: %v", opens)
+
+	if opens {
+		t.Error("on an empty state directory, a cookie from before still " +
+			"opens the generator page")
+	}
+
+	if !opensGeneratorPage(t, restarted, logIn(t, restarted)) {
+		t.Error("a login on an empty state directory does not open the " +
+			"generator page")
+	}
+}