REST API: test GET v1/pems with empty response

pkg/rest/allpems_handler_test.go

@@ -309,6 +309,22 @@ func TestAllPems(t *testing.T) {
 		t.Errorf("HEAD /v1/pems Content-Type: got %s want %s",
 			rr.Header().Get("Content-Type"), jsonContentType)
 	}
+
+	delete(files.Files, "ns1/cafe")
+	delete(files.Files, "ns2/bar")
+	req = httptest.NewRequest(http.MethodGet, "/v1/pems", nil)
+	rr = httptest.NewRecorder()
+	hndlr.ServeHTTP(rr, req)
+	if rr.Code != http.StatusOK {
+		t.Errorf("GET /v1/pems status: got %d want %d", rr.Code,
+			http.StatusOK)
+	}
+	if err = json.Unmarshal(rr.Body.Bytes(), &allInfo); err != nil {
+		t.Errorf("GET /v1/pems unmarshal: %v", err)
+	}
+	if len(allInfo) != 0 {
+		t.Fatalf("GET /v1/pems len(slice) got %d want 0", len(allInfo))
+	}
 }
 
 func TestAllPems405(t *testing.T) {