If you mean Google: Yes, extensive. One of the techniques they use is DiRT (Disaster Recovery Testing) which is a scheduled time-frame in which Google purposefully breaks systems that are exceeding their SLAs to verify that automated recovery executes as intended. In general, a DiRT test would catch something like "This service has a key dependency on us-east-1."
Now, in the past (also a Xoogler)... Some pieces of Cloud were moving at a cadence that they got away with a bit of a relaxed DiRT awhile back, so if someone tells me "I remember when a us-east-1 outage took down a key Cloud service" I would believe it. DiRT is also planned testing, it's not slapping a chaos monkey on the cluster fabric and crossing one's fingers, so it's entirely possible for key outage modalities to get missed (engineers are human and even though Google aims for a "no haunted closets" engineering practice, people develop a sixth sense of where the weak parts are of your infra and it takes courage to commit to pushing on those until they break).
Which 'they?'
If you mean Google: Yes, extensive. One of the techniques they use is DiRT (Disaster Recovery Testing) which is a scheduled time-frame in which Google purposefully breaks systems that are exceeding their SLAs to verify that automated recovery executes as intended. In general, a DiRT test would catch something like "This service has a key dependency on us-east-1."
Now, in the past (also a Xoogler)... Some pieces of Cloud were moving at a cadence that they got away with a bit of a relaxed DiRT awhile back, so if someone tells me "I remember when a us-east-1 outage took down a key Cloud service" I would believe it. DiRT is also planned testing, it's not slapping a chaos monkey on the cluster fabric and crossing one's fingers, so it's entirely possible for key outage modalities to get missed (engineers are human and even though Google aims for a "no haunted closets" engineering practice, people develop a sixth sense of where the weak parts are of your infra and it takes courage to commit to pushing on those until they break).
Google SRE's official (?) motto is "hope is not a strategy".