Rep. Alexandria Ocasio-Cortez (D-N.Y.) recently defended the idea of "purity tests" in the Democratic Party, saying it's justifiable to criticize candidates who take donations from wealthy people.

Problem is, Ocasio-Cortez herself received a financial boost from billionaire Tom Steyer, who was very active in funding political causes before deciding to run for president this year.

"For anyone who accuses us for instituting purity tests — it's called having values," Ocasio-Cortez said at a Sen. Bernie Sanders rally, according to the New York Post. "It's called giving a damn. It's called having standards for your conduct to not be funded by billionaires but to be funded by the people.

"I go into work all the time and I hear people say, 'What will my donors think?' I hear that phrase," Ocasio-Cortez also said. "I hear and I see that billionaires get members of Congress on speed dial and waitresses don't."

Ocasio-Cortez's campaign received a $2,700 donation from Steyer through his family office, Fahr LLC.

While that's not an overwhelming amount of money, it's certainly many times larger than a donation a candidate might receive from a typical working voter in The Bronx or Queens, and it raises the question: How many donations can one accept from a billionaire before failing a purity test?

According to OpenSecrets.org, Ocasio-Cortez raised more than $2 million during her 2018 election campaign.

The issue of purity tests and wealthy donors has become a central issue in the 2020 Democratic presidential primary. Sen. Elizabeth Warren (D-Mass.) has attacked South Bend, Indiana, Mayor Pete Buttigieg for hosting fundraisers attended by millionaires and billionaires.

Buttigieg has defended those fundraisers by pointing out that Warren herself is much wealthier than he is, and it has since been highlighted that Warren has her own history of courting wealthy donors, even though she says she no longer does so.