Flight tests were planned for 1966, the mission was scheduled for 1967-1968.
The ground experimental development of complex N1-L3 included:

• strength and pressure integrity tests, testing under hard vacuum and in space environment;
• testing of mechanical and pyrotechnic separation and docking systems, pneudraulic systems of LV stages and system L3, instruments and equipment of control and measuring systems, power systems, fixture, life support systems, high temperature and thermal-vacuum tests, investigation of gas-dynamic processes during launch and stage separation;
• test simulation of LV stages including thermodynamic processes encountered while fueling tanks, during storage and pre-launch processing;
• integrated testing of LV together with the launch pad including verification of thermodynamic processes of the ground complex fuel systems, mating systems of the rocket complex and the launch site, pre-launch processing of the launch site and the rocket complex.

The ground strength testing included static, dynamic, and impact testis of the complex assemblies and equipment.
The integrated ground tests, functional tests of propulsion units and stages, temperature, dynamic, and vibration testing of LV N1 and its upper stage were carried out on a specially modified facility in a period from 1965 to 1974.
At that time, "cold" tests of stages B, V, G, and D were performed without burning engines to verify fueling modes, pre-launch pressurization, cooling down, drainage, etc.
The tests included:

• four firing tests of the full-scale stage B with four engines of a total thrust sized to about 600 tf carried out on February 2, April 13, August 23, 1967 and November 25, 1970;
• three firing tests of the full-scale stage B with eight engines of a total thrust sized to 1200 tf carried out on June 23, 1968, August 29, 1970, and December 15, 1973;
• a cycle of firing tests carried out on a reusable setup simulating nominal operating conditions of individual engines of stage A;
• firing tests of stage G and stage D.

All tests were successful and, relying on their results, all stages were certified for flight tests.