Fix

Author: st0012

.github/workflows/test.yml

@@ -35,14 +35,8 @@ jobs:
           ruby-version: ${{ matrix.ruby }}
           bundler-cache: true
 
-      - name: Debug - run fib benchmark directly
-        run: bundle exec ruby -I harness benchmarks/fib.rb
-
-      - name: Run CLI integration tests in isolation
-        run: bundle exec ruby -Ilib:test test/benchmark_runner_cli_test.rb --verbose --name "/parses ARGV/"
-
       - name: Run tests
-        run: bundle exec rake test --trace
+        run: bundle exec rake test
 
   benchmark-default:
     runs-on: ubuntu-latest

lib/benchmark_suite.rb

@@ -180,6 +180,15 @@ def benchmark_env(ruby)
       end
     end
 
+    # Clear Bundler environment variables to prevent the parent's bundle context
+    # from leaking into benchmark subprocesses. Benchmarks that need Bundler will
+    # set up their own context via use_gemfile in the harness.
+    # This is especially important when running tests under `bundle exec rake test`.
+    ["BUNDLE_GEMFILE", "BUNDLE_BIN_PATH", "BUNDLE_PATH", "BUNDLER_VERSION",
+     "BUNDLER_SETUP", "RUBYOPT", "RUBYLIB"].each do |var|
+      env[var] = nil if ENV.key?(var)
+    end
+
     env
   end