As pointed out by shellcheck:

> In test/stats.bats line 72:
>     run crictl stats -o json "$crt2_id"
>                               ^------^ SC2154: crt2_id is referenced but not assigned.

The test works just fine though, because

 1. it is the same as running crictl stats without ID, in which case it
    shows stats for all IDs.

 2. the values obtained are not compared in any way, just printed.

Signed-off-by: Kir Kolyshkin <[email protected]>

1. Make sure we actually compare the memory usage, rather than merely
   printing it. Add a comment describing what we're doing here.

2. Use "here file" instead of echo.

3. Make sure stats are provided for the given id.

4. Consolidate getting memory usage so there are less temp variables.

5. When possible, use

	var=$(cmd ... 2>&1)
	echo "$var"

   instead of

	run cmd ...
	[ "$status" -eq 0 ]
	echo "$output"
	var="$output"

   They are roughly the same, and `set -e` (set by bats) implicitly
   checks the exit code. The `2>&1` stance is needed to see the error

Signed-off-by: Kir Kolyshkin <[email protected]>

container_redis.json seems to intermittantly exit, which makes using it
as the basis for comparison for stats tretcherous.

Signed-off-by: Peter Hunt <[email protected]>

it is much less likely two containers will use the same amount of memory if they're different containers

Signed-off-by: Peter Hunt <[email protected]>

as it can be unmounted multiple times and should not result in an error

Signed-off-by: Peter Hunt <[email protected]>