Fix traffic map zoom and add paginated history with local city GeoIP

traffic_city_test.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"compress/gzip"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCityInstallRejectsBadDownload(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv("DASHBOARD_DB_PATH", filepath.Join(dir, "dashboard.db"))
+	existing := []byte("existing database")
+	if err := os.WriteFile(trafficCityPath(), existing, 0600); err != nil {
+		t.Fatal(err)
+	}
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		g := gzip.NewWriter(w)
+		g.Write([]byte("corrupt database"))
+		g.Close()
+	}))
+	defer server.Close()
+	if err := installTrafficCityFrom(server.URL, cityDatabaseSHA1); err == nil {
+		t.Fatal("bad checksum accepted")
+	}
+	got, err := os.ReadFile(trafficCityPath())
+	if err != nil || string(got) != string(existing) {
+		t.Fatal("existing database replaced on failure")
+	}
+	files, _ := filepath.Glob(filepath.Join(dir, ".city-*"))
+	if len(files) != 0 {
+		t.Fatal("partial file left behind")
+	}
+}
+func TestCityDatabaseDownloaded(t *testing.T) {
+	source := os.Getenv("DASHBOARD_CITY_TEST_GZIP")
+	if source == "" {
+		t.Skip("optional official database integration test")
+	}
+	t.Setenv("DASHBOARD_DB_PATH", filepath.Join(t.TempDir(), "dashboard.db"))
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { http.ServeFile(w, r, source) }))
+	defer server.Close()
+	trafficCityReady()
+	if err := installTrafficCityFrom(server.URL, cityDatabaseSHA1); err != nil {
+		t.Fatal(err)
+	}
+	city, region := lookupTrafficCity("20.194.96.114")
+	t.Logf("city=%q region=%q", city, region)
+	if city == "" {
+		t.Fatal("public IP city not decoded")
+	}
+}