Small changes in response to review.

          name = "${pname}-interactive-environment";

          nativeBuildInputs = [ wrappedRuby basicEnv ];

          shellHook = ''

            export OLD_IRBRC="$IRBRC"

            export OLD_IRBRC=$IRBRC

            export IRBRC=${irbrc}

          '';

          buildCommand = ''

#!/usr/bin/env bash

set -o xtrace

pwd

cd $(dirname $0)

find . -name text.nix

testfiles=$(find . -name test.nix)

nix-build -E "with import <nixpkgs> {}; callPackage testing/driver.nix { testFiles = [ $testfiles ]; }" --show-trace && cat result

  testLine = report: "${okStr report} ${toString (report.index + 1)} ${report.description}" + testDirective report + testYaml report;

  # These are part of the TAP spec, not yet implemented.

  #c.f.  https://github.com/NixOS/nixpkgs/issues/27071

  testDirective = report: "";

  testYaml = report: "";

  okStr = { result, ...}: if result == "pass" then "ok" else "not ok";