Facing mounting pressure over testing problems that have plagued Tennessee for three years, Education Commissioner Candice McQueen goes before lawmakers Wednesday to explain what went wrong this time — and what the state is doing about it.

McQueen is scheduled to appear at noon before a joint legislative hearing of several committees, and she’s expected to recount some of the same things she shared in an email Tuesday evening with district superintendents.

The former classroom teacher and university dean said she was “completely devastated” Tuesday morning when technical problems derailed online testing for a second state day.

She announced a three-day extension of this spring’s online testing window to May 9 to provide schools with more flexibility because of the problems.

She reported that, despite the snafus, more than 120,000 tests were completed on Monday and Tuesday.

And she was contrite. “I want to personally apologize to each of you and to your many staff, teachers, and students who have been handling these issues with patience and a positive attitude. We are very grateful,” she wrote.

But the reception on Capitol Hill in Nashville is not expected to be friendly, even as McQueen has numerous fans there for sticking by major reforms approved by the legislature in 2010 as part of Tennessee’s First to the Top education overhaul.

This week, lawmakers have gotten an earful from educators and parents angry that TNReady wasted two school days for older students who were supposed to take the standardized test online. Only last fall, McQueen had assured lawmakers she’d put an end to TNReady problems when scoring errors emerged in the second year of testing.

The anger reached a boiling point on Tuesday, with House Democrats calling for McQueen to step down and Republicans discussing last-minute legislation that would clip TNReady’s wings.

“We’re fed up,” said Rep. Mike Stewart, a Nashville Democrat who chairs his party’s caucus. “Commissioner McQueen had one thing she had to do this year, and she failed. We need another commissioner.”

But lawmakers can’t fire McQueen. Only Gov. Bill Haslam can do that, and he’s the one who hired her in late 2014. The Republican governor also has championed his education commissioner through good and bad — including the failed rollout of online testing in 2016 and Tennessee’s big gains on national tests from 2011 to 2015.

Asked about the legislative saber-rattling, a Haslam spokeswoman said the governor has “complete confidence in Commissioner McQueen” and called for patience while the state and Questar investigate a “deliberate attack” by hackers on the testing company’s data system — the alleged source of Tuesday’s testing problems.

"The governor has complete confidence in Commissioner McQueen."Jennifer Donnals, spokeswoman

“This was an outside attack on the testing system, and the system worked as designed to protect private student information,” the spokeswoman, Jennifer Donnals, said in a statement. “Eliminating testing as a response would only serve to accomplish the very disruption the hackers intended. The governor understands and shares the frustration of teachers, students and parents and appreciates their patience while this attack is being investigated.”

Meanwhile, lawmakers barreling toward the finish line of this year’s legislative session huddled to seek legislative remedies to this week’s testing failures via a bill sponsored by Rep. John DeBerry of Memphis and Sen. Brian Kelsey of Germantown. One amendment would require the state to administer only paper-and-pencil tests in future years. A second would require the state Department of Education to “hold harmless” students, teachers, schools, and districts for the results of this year’s TNReady tests, which are incorporated into teacher evaluations and students’ final grades and determine which low-performing schools will face intervention.