1 files changed, 129 insertions, 0 deletions
diff --git a/spec/config/inject_enterprise_edition_module_spec.rb b/spec/config/inject_enterprise_edition_module_spec.rb
new file mode 100644
index 00000000000..61b40e46001
--- /dev/null
+++ b/spec/config/inject_enterprise_edition_module_spec.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+RSpec.describe InjectEnterpriseEditionModule do
+  let(:extension_name) { 'FF' }
+  let(:extension_namespace) { Module.new }
+  let(:fish_name) { 'Fish' }
+  let(:fish_class) { Class.new }
+  let(:fish_extension) { Module.new }
+
+  before do
+    # Make sure we're not relying on which mode we're running under
+    allow(Gitlab).to receive(:extensions).and_return([extension_name.downcase])
+
+    # Test on an imagined extension and imagined class
+    stub_const(fish_name, fish_class) # Fish
+    allow(fish_class).to receive(:name).and_return(fish_name)
+  end
+
+  shared_examples 'expand the extension with' do |method|
+    context 'when extension namespace is set at top-level' do
+      before do
+        stub_const(extension_name, extension_namespace) # FF
+        extension_namespace.const_set(fish_name, fish_extension) # FF::Fish
+      end
+
+      it "calls #{method} with the extension module" do
+        expect(fish_class).to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod_with", fish_name)
+      end
+    end
+
+    context 'when extension namespace is set at another namespace' do
+      let(:another_namespace) { Module.new } # QA
+
+      before do
+        another_namespace.const_set(extension_name, extension_namespace) # QA::FF
+        extension_namespace.const_set(fish_name, fish_extension) # QA::FF::Fish
+      end
+
+      it "calls #{method} with the extension module from the additional namespace" do
+        expect(fish_class).to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod_with", fish_name, namespace: another_namespace)
+      end
+    end
+
+    context 'when extension namespace exists but not the extension' do
+      before do
+        stub_const(extension_name, extension_namespace) # FF
+      end
+
+      it "does not call #{method}" do
+        expect(fish_class).not_to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod_with", fish_name)
+      end
+    end
+
+    context 'when extension namespace does not exist' do
+      it "does not call #{method}" do
+        expect(fish_class).not_to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod_with", fish_name)
+      end
+    end
+  end
+
+  shared_examples 'expand the assumed extension with' do |method|
+    context 'when extension namespace is set at top-level' do
+      before do
+        stub_const(extension_name, extension_namespace) # FF
+        extension_namespace.const_set(fish_name, fish_extension) # FF::Fish
+      end
+
+      it "calls #{method} with the extension module" do
+        expect(fish_class).to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod")
+      end
+    end
+
+    context 'when extension namespace exists but not the extension' do
+      before do
+        stub_const(extension_name, extension_namespace) # FF
+      end
+
+      it "does not call #{method}" do
+        expect(fish_class).not_to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod")
+      end
+    end
+
+    context 'when extension namespace does not exist' do
+      it "does not call #{method}" do
+        expect(fish_class).not_to receive(method).with(fish_extension)
+
+        fish_class.__send__("#{method}_mod")
+      end
+    end
+  end
+
+  describe '#prepend_mod_with' do
+    it_behaves_like 'expand the extension with', :prepend
+  end
+
+  describe '#extend_mod_with' do
+    it_behaves_like 'expand the extension with', :extend
+  end
+
+  describe '#include_mod_with' do
+    it_behaves_like 'expand the extension with', :include
+  end
+
+  describe '#prepend_mod' do
+    it_behaves_like 'expand the assumed extension with', :prepend
+  end
+
+  describe '#extend_mod' do
+    it_behaves_like 'expand the assumed extension with', :extend
+  end
+
+  describe '#include_mod' do
+    it_behaves_like 'expand the assumed extension with', :include
+  end
+end