1 files changed, 97 insertions, 0 deletions
diff --git a/spec/lib/gitlab/utils/delegator_override_spec.rb b/spec/lib/gitlab/utils/delegator_override_spec.rb
new file mode 100644
index 00000000000..af4c7fa5d8e
--- /dev/null
+++ b/spec/lib/gitlab/utils/delegator_override_spec.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+RSpec.describe Gitlab::Utils::DelegatorOverride do
+  let(:delegator_class) do
+    Class.new(::SimpleDelegator) do
+      extend(::Gitlab::Utils::DelegatorOverride)
+
+      def foo
+      end
+    end
+  end
+
+  let(:target_class) do
+    Class.new do
+      def foo
+      end
+
+      def bar
+      end
+    end
+  end
+
+  let(:dummy_module) do
+    Module.new do
+      def foobar
+      end
+    end
+  end
+
+  before do
+    stub_env('STATIC_VERIFICATION', 'true')
+  end
+
+  describe '.delegator_target' do
+    subject { delegator_class.delegator_target(target_class) }
+
+    it 'sets the delegator target to the validator' do
+      expect(described_class.validator(delegator_class))
+        .to receive(:add_target).with(target_class)
+
+      subject
+    end
+
+    context 'when the class does not inherit SimpleDelegator' do
+      let(:delegator_class) do
+        Class.new do
+          extend(::Gitlab::Utils::DelegatorOverride)
+        end
+      end
+
+      it 'raises an error' do
+        expect { subject }.to raise_error(ArgumentError, /not a subclass of 'SimpleDelegator' class/)
+      end
+    end
+  end
+
+  describe '.delegator_override' do
+    subject { delegator_class.delegator_override(:foo) }
+
+    it 'adds the method name to the allowlist' do
+      expect(described_class.validator(delegator_class))
+        .to receive(:add_allowlist).with([:foo])
+
+      subject
+    end
+  end
+
+  describe '.delegator_override_with' do
+    subject { delegator_class.delegator_override_with(dummy_module) }
+
+    it 'adds the method names of the module to the allowlist' do
+      expect(described_class.validator(delegator_class))
+        .to receive(:add_allowlist).with([:foobar])
+
+      subject
+    end
+  end
+
+  describe '.verify!' do
+    subject { described_class.verify! }
+
+    it 'does not raise an error when an override is in allowlist' do
+      delegator_class.delegator_target(target_class)
+      delegator_class.delegator_override(:foo)
+
+      expect { subject }.not_to raise_error
+    end
+
+    it 'raises an error when there is an override' do
+      delegator_class.delegator_target(target_class)
+
+      expect { subject }.to raise_error(Gitlab::Utils::DelegatorOverride::Validator::UnexpectedDelegatorOverrideError)
+    end
+  end
+end