Mayor Rob Ford at Toronto City Hall on July 28, 2014

Toronto Mayor Rob Ford says he is sober as a judge, but won't take a test to prove it unless other mayoral candidates do the same. (CBC)

After already accepting and completing the ALS ice bucket challenge, Toronto mayor Rob Ford is facing another challenge this week: a drug and alcohol test.

The challenge comes from mayoral candidate Sarah Thomson, who proposed that all mayoral candidates take sobriety tests. It was a direct challenge to Ford. The mayor admitted to abusing drugs and alcohol for at least 15 years since before he was a city councillor, and sought treatment earlier this summer in a rehab facility.

Thomson released what she claims are the results of a drug test on Wednesday as proof that she does not use drugs. "I often get asked if I do drugs, and I wanted to assure all Toronto residents that I do not have any alcohol or addiction issues," she said.

Ford said he would be the first to take a test, but only if all the other candidates do also.

"I have not touched drugs or alcohol in months," said Ford when approached with the challenge on Wednesday.

Ford repeated the claim he is a "as clean as a whistle" and "as sober as a judge" — a fact he said that "everybody knows."

Then he proposed that all councillors also take tests, as well as school trustees. He then mused the drug tests could be for all candidates running for those positions, as well as all civil servants — illustrating his point that anyone at city hall, including those in the media, could fail a drug test.

Ford summed up the challenge as another example of his opponents hoping he succumbs to his addiction problems.

"Some people want to see me fail," he said. "It's not going to happen."