[Features][test-lib] Add message arg to the check function

[cschot]

I would like to propose a change to the check function of the dev-container-features-test-lib script.

The function should take a message to display when the test fails, like other testing frameworks have.

The current function code is:

cli/src/spec-node/featuresCLI/utils.ts

Lines 75 to 91 in c246645

	check() {
	LABEL=$1
	shift
	echo -e "\n"
	echo -e "🔄 Testing '$LABEL'"
	echo -e '\\033[37m'
	if "$@"; then
	echo -e "\n"
	echo "✅ Passed '$LABEL'!"
	return 0
	else
	echo -e "\n"
	echoStderr "❌ $LABEL check failed."
	FAILED+=("$LABEL")
	return 1
	fi
	}

I propose to add a message on $2 or the last argument.
Any thoughts on this?

I would suggest something like this:

check() { 
     LABEL=$1 
     MESSAGE = $2 or ${!#}
 
     #
     # the rest of the function
     #
 } 

The new function should work like the examples below, and be backwards compatible

old: 
check "java version LTS installed as default" \
          grep "LTS" <(java --version)

new:
check "java version LTS installed as default" \
         grep "LTS" <(java --version) \
        "REASON: The installed version is: $(java --version)"

or 

check "java version LTS installed as default"  \
        "REASON: The installed version is: $(java --version)" \
        grep "LTS" <(java --version)

[cschot]

I tested some combinations, but it looks difficult to add the MESSAGE arg to the check() function.

When using MESSAGE as $2 it is not backwards compatible, because $2 and up was the command to check.

When using MESSAGE as the last arg ( ${!#} ) it is also not backwards compatible, because the last arg was (a portion of) the command to check.