CRJ-700 Captain reported the malfunction of bleed valves; pressurization and a malfunctioning autopilot.

Narrative

Received aircraft that was just test flown out of the maintenance base in ZZZ. Deferred APU and Ignition System A.Took off from ZZZ to ZZZ1. Climbing around 14000 feet; L BLEED DUCT warning come on which then became a L BLEED DUCT CAUTION. Ran QRH 7-22. Both L and R engine bleed valves were closed. Initiated an immediate descent to 10000 feet; and followed 'Unpressurized Flight Procedure' on QRH 7-26 as per the previous QRH procedure ran.After we started heading back to ZZZ; the autopilot disconnected with the disconnected aural constantly sounding. We clicked all A/P disengage buttons to see if it would silence; but it kept on sounding. Instructed the FO to turn off DCU1 and DCU2 (one at a time to see if any specific one was affecting the aural warning) both needed to be turned off to silence.Heading bug was non-functional (except for the center heading function). Only 1 FCC light was light. Re-attempted to engage Autopilot with no success.FO and I switched roles; I became pilot flying since I had been flying most of the day with autopilot off. Landed without further issues in ZZZ.Cause: known beyond speculation.