The test runners cql-pytest/run et al. try to automatically find the
last-compile Scylla executable, but this decision can be overriden by
the SCYLLA environment variable. If the user sets by mistake SCYLLA to
something which is not a valid path of an executable, the result was a
long and obscure Python stack trace.
So after this patch, if SCYLLA points to something which is not an
executable, a clear error is produced immediately, directing the user
to set it this variable to a correct executable
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20220323164427.3301828-1-nyh@scylladb.com>