code: function findRuntimePath() {
      const upPkg = readPkgUp.sync();
      // case 1: we're in NR itself
      if (upPkg.pkg.name === 'node-red') {
          if (checkSemver(upPkg.pkg.version,"<0.20.0")) {
              return path.join(path.dirname(upPkg.path), upPkg.pkg.main);
          } else {
              return path.join(path.dirname(upPkg.path),"packages","node_modules","node-red");
          }
      }
      // case 2: NR is resolvable from here
      try {
          return require.resolve('node-red');
      } catch (ignored) {}
      // case 3: NR is installed alongside node-red-node-test-helper
      if ((upPkg.pkg.dependencies && upPkg.pkg.dependencies['node-red']) ||
          (upPkg.pkg.devDependencies && upPkg.pkg.devDependencies['node-red'])) {
          const dirpath = path.join(path.dirname(upPkg.path), 'node_modules', 'node-red');
          try {
              const pkg = require(path.join(dirpath, 'package.json'));
              return path.join(dirpath, pkg.main);
          } catch (ignored) {}
      }
  }
docs: Finds the NR runtime path by inspecting environment