Add tests with different flag combinations

Since this PR was made because we missed checking
RuboCop offenses with different flags, therefore
adding tests so that all flag combinations are
tested.

Signed-off-by: Utkarsh Gupta <utkarsh@debian.org>

bundler/spec/commands/newgem_spec.rb

@@ -10,6 +10,15 @@ def gem_skeleton_assertions
     expect(bundled_app("#{gem_name}/lib/#{require_path}/version.rb")).to exist
   end
 
+  def bundle_exec_rubocop
+    prepare_gemspec(bundled_app(gem_name, "#{gem_name}.gemspec"))
+    rubocop_version = RUBY_VERSION > "2.4" ? "0.85.1" : "0.80.1"
+    gems = ["minitest", "rake", "rake-compiler", "rspec", "rubocop -v #{rubocop_version}", "test-unit"]
+    path = Bundler.feature_flag.default_install_uses_path? ? local_gem_path(:base => bundled_app(gem_name)) : system_gem_path
+    realworld_system_gems gems, :path => path
+    bundle "exec rubocop --config .rubocop.yml", :dir => bundled_app(gem_name)
+  end
+
   let(:generated_gemspec) { Bundler.load_gemspec_uncached(bundled_app(gem_name).join("#{gem_name}.gemspec")) }
 
   let(:gem_name) { "mygem" }
@@ -174,17 +183,6 @@ def gem_skeleton_assertions
     it "generates a default .rubocop.yml" do
       expect(bundled_app("#{gem_name}/.rubocop.yml")).to exist
     end
-
-    it "runs rubocop inside the generated gem with no offenses" do
-      skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
-      prepare_gemspec(bundled_app(gem_name, "#{gem_name}.gemspec"))
-      rubocop_version = RUBY_VERSION > "2.4" ? "0.85.1" : "0.80.1"
-      gems = ["rake", "rubocop -v #{rubocop_version}"]
-      path = Bundler.feature_flag.default_install_uses_path? ? local_gem_path(:base => bundled_app(gem_name)) : system_gem_path
-      realworld_system_gems gems, :path => path
-      bundle "exec rubocop --config .rubocop.yml", :dir => bundled_app(gem_name)
-      expect(err).to be_empty
-    end
   end
 
   shared_examples_for "--no-rubocop flag" do
@@ -214,6 +212,41 @@ def gem_skeleton_assertions
     end
   end
 
+  it "has no rubocop offenses when using --rubocop flag" do
+    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    bundle "gem #{gem_name} --rubocop"
+    bundle_exec_rubocop
+    expect(err).to be_empty
+  end
+
+  it "has no rubocop offenses when using --ext and --rubocop flag" do
+    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    bundle "gem #{gem_name} --ext --rubocop"
+    bundle_exec_rubocop
+    expect(err).to be_empty
+  end
+
+  it "has no rubocop offenses when using --ext, --test=minitest, and --rubocop flag" do
+    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    bundle "gem #{gem_name} --ext --test=minitest --rubocop"
+    bundle_exec_rubocop
+    expect(err).to be_empty
+  end
+
+  it "has no rubocop offenses when using --ext, --test=rspec, and --rubocop flag" do
+    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    bundle "gem #{gem_name} --ext --test=rspec --rubocop"
+    bundle_exec_rubocop
+    expect(err).to be_empty
+  end
+
+  it "has no rubocop offenses when using --ext, --ext=test-unit, and --rubocop flag" do
+    skip "ruby_core has an 'ast.rb' file that gets in the middle and breaks this spec" if ruby_core?
+    bundle "gem #{gem_name} --ext --test=test-unit --rubocop"
+    bundle_exec_rubocop
+    expect(err).to be_empty
+  end
+
   shared_examples_for "CI config is absent" do
     it "does not create any CI files" do
       expect(bundled_app("#{gem_name}/.github/workflows/main.yml")).to_not exist