diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index 24a6eb9e..511a5bb0 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -117,6 +117,17 @@ func TestLibraryEnvOverrides(t *testing.T) {
 	}
 }
 
+func TestSubsonicEnvOverride(t *testing.T) {
+	t.Setenv("SMARTMUSIC_SUBSONIC_ALLOW_PLAINTEXT_PASSWORD", "true")
+	cfg, err := Load("")
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if !cfg.Subsonic.AllowPlaintextPassword {
+		t.Error("allow_plaintext_password = false, want true")
+	}
+}
+
 func TestLibraryYAMLLoads(t *testing.T) {
 	dir := t.TempDir()
 	path := filepath.Join(dir, "config.yaml")