Fix broken tests and shellcheck issues (#7)

- Fix broken tests (`devcontainer` CLI no longer seems to output
  everything to stderr, so remove redirection)
- Fix minor quoting issues identified by shellcheck

Author: csutter

test/barebones-ruby/test.sh

@@ -4,7 +4,7 @@ source "$(dirname "$0")/../harness.sh"
 
 setup "barebones-ruby" "3.2.0"
 
-run_test "Ruby version is correct" "ruby -v" $IMAGE_TAG
+run_test "Ruby version is correct" "ruby -v" "$IMAGE_TAG"
 run_test "Sample script runs" "ruby sample.rb" "Hello world"
 run_test "Container defaults to non-root user" "whoami" "devcontainer"
 run_test "Non-root user is able to sudo" "sudo whoami" "root"

test/harness.sh

@@ -70,7 +70,7 @@ run_test() {
   #
   # We _want_ $cmd to be split here as it could include arguments:
   # shellcheck disable=SC2086
-  result=$(devcontainer exec --workspace-folder "$TEST_DIR" --id-label "$ID_LABEL" $cmd 2>&1 1> /dev/null || true)
+  result=$(devcontainer exec --workspace-folder "$TEST_DIR" --id-label "$ID_LABEL" $cmd || true)
 
   case "$result" in
     *$expected_result*)
@@ -93,6 +93,6 @@ end_tests() {
 
   # Succeed if there are no failed tests, but also make sure that at least one test has passed
   # (otherwise something else might have gone wrong)
-  [ $FAILED_TESTS -eq 0 ] && [ $PASSED_TESTS -gt 0 ]
+  [ "$FAILED_TESTS" -eq 0 ] && [ "$PASSED_TESTS" -gt 0 ]
 }
 trap "end_tests" EXIT