Const. Shyldon Safruk took the stand at the Ottawa Court House on Tuesday during his trial for assault causing bodily harm. (CBC)

An Ottawa police officer testified Tuesday that he pushed a taxi driver, but did so only in self-defence.

Const. Shyldon Safruk, 36, is being tried for assault causing bodily harm in a May 11, 2009, incident in which a taxi driver alleges that Safruk, in a fit of road rage, threw him to the ground and shouted a racial slur at him.

Safruk told court he had just finished work that day and was driving on the Airport Parkway when a merging taxi driven by Sami Aldoboni, 44, forced him into oncoming traffic. He said he could have been killed.

Safruk then followed the taxi driver to the airport waiting area with the idea he would have a talk with the driver and perhaps charge him with dangerous driving, court heard. He testified once he confronted Aldoboni, the driver took a swing at him but missed, losing his balance, falling and breaking his wrist and finger.

On Monday, Aldoboni testified it was Safruk who almost drove him off the road. He said Safruk then assaulted him while uttering a racial slur.

Safruk denied making any racial remarks.

"I did not say that," he told court. "That's not the kind of person I am."

The court is set to hear closing arguments from both sides Wednesday, and the judge is expected to render a verdict by Friday.