database: add FormatDSN

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

database/dsn_test.go

@@ -1,6 +1,7 @@
 package database
 
 import (
+	"net/url"
 	"testing"
 )
 
@@ -13,3 +14,18 @@ func TestParseDSN(t *testing.T) {
 		t.Fatalf("parsing error")
 	}
 }
+
+func TestFormatDSN(t *testing.T) {
+	src := "postgres://username:p@ssword#@host:12345/dbname?key1=val2&key2=val2"
+	cfg, err := ParseDSN(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dst, err := url.PathUnescape(cfg.FormatDSN())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if src != dst {
+		t.Fatalf("\n%s\n%s", src, dst)
+	}
+}