Here is a Shodokan Aikido video clip I grabbed off YouTube. Shodokan Aikido is also known as Tomiki-style Aikido. That is the style that I do, so I know it better than the more traditional Aikido styles.
This video is by British Aikidoka* who calls himself pixelIMEDIA2004, and shows two Yondan 4th-degree black belts performing the Goshin Ho kata as part of their grading to Godan (5th degree black belt).
Please understand this is not sparring. It is not a fight. These Aikido techniques are far too dangerous to be done randomly unless both aikidoka are very highly skilled. It is a kata, that is a pre-arranged sequence of martial arts moves.
Both men are at a very well-matched skill level. It is just that one takes the turn of being the “attacker” so his partner can demonstrate the correct responses to these simulated attacks.
As soon as one has done all the defenses, then they will bow and change roles, so the attacker now gets his turn to play defender. This way the risks of any injury are minimized.
To actually test their skill level against a resisting opponent, Tomiki style Aikido (aka Shodokan) then uses randori (free practice, same as does Judo), and also shiai (competition).
Traditional Aikido styles do not have randori or shiai, because their founder (O-Sensei) feared it would give the students big egos… i.e. they might go around thinking they were tough guys, and he strongly disapproved of that.
*Aikidoka is Japanese word. It just means a person who trains at Aikido. In the same manner, a person who trains at Judo is called a Judoka, and one who does Karate is a Karateka.