diff --git a/Library/Homebrew/test/language/python/virtualenv_spec.rb b/Library/Homebrew/test/language/python/virtualenv_spec.rb
index 539039bf99..f5e03653db 100644
--- a/Library/Homebrew/test/language/python/virtualenv_spec.rb
+++ b/Library/Homebrew/test/language/python/virtualenv_spec.rb
@@ -94,7 +94,7 @@ describe Language::Python::Virtualenv::Virtualenv, :needs_python do
       FileUtils.touch src_bin/"kilroy"
       bin_after = Dir.glob(src_bin/"*")
 
-      expect(virtualenv).to receive(:pip_install).with("foo")
+      expect(virtualenv).to receive(:pip_install).with("foo", { build_isolation: true })
       expect(Dir).to receive(:[]).with(src_bin/"*").twice.and_return(bin_before, bin_after)
 
       virtualenv.pip_install_and_link "foo"
@@ -123,7 +123,7 @@ describe Language::Python::Virtualenv::Virtualenv, :needs_python do
       FileUtils.touch src_man/"man5/kilroy.5"
       man_after = Dir.glob(src_man/"**/*")
 
-      expect(virtualenv).to receive(:pip_install).with("foo")
+      expect(virtualenv).to receive(:pip_install).with("foo", { build_isolation: true })
       expect(Dir).to receive(:[]).with(src_bin/"*").and_return([])
       expect(Dir).to receive(:[]).with(src_man/"man*/*").and_return(man_before)
       expect(Dir).to receive(:[]).with(src_bin/"*").and_return([])