1 files changed, 78 insertions, 0 deletions
diff --git a/spec/lib/gitlab/graphql/batch_key_spec.rb b/spec/lib/gitlab/graphql/batch_key_spec.rb
new file mode 100644
index 00000000000..881fba5c1be
--- /dev/null
+++ b/spec/lib/gitlab/graphql/batch_key_spec.rb
@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require 'test_prof/recipes/rspec/let_it_be'
+
+RSpec.describe ::Gitlab::Graphql::BatchKey do
+  let_it_be(:rect) { Struct.new(:len, :width) }
+  let_it_be(:circle) { Struct.new(:radius) }
+  let(:lookahead) { nil }
+  let(:object) { rect.new(2, 3) }
+
+  subject { described_class.new(object, lookahead, object_name: :rect) }
+
+  it 'is equal to keys of the same object, regardless of lookahead or object name' do
+    expect(subject).to eq(described_class.new(rect.new(2, 3)))
+    expect(subject).to eq(described_class.new(rect.new(2, 3), :anything))
+    expect(subject).to eq(described_class.new(rect.new(2, 3), lookahead, object_name: :does_not_matter))
+    expect(subject).not_to eq(described_class.new(rect.new(2, 4)))
+    expect(subject).not_to eq(described_class.new(circle.new(10)))
+  end
+
+  it 'delegates attribute lookup methods to the inner object' do
+    other = rect.new(2, 3)
+
+    expect(subject.hash).to eq(other.hash)
+    expect(subject.len).to eq(other.len)
+    expect(subject.width).to eq(other.width)
+  end
+
+  it 'allows the object to be named more meaningfully' do
+    expect(subject.object).to eq(object)
+    expect(subject.object).to eq(subject.rect)
+  end
+
+  it 'works as a hash key' do
+    h = { subject => :foo }
+
+    expect(h[described_class.new(object)]).to eq(:foo)
+  end
+
+  describe '#requires?' do
+    it 'returns false if the lookahead was not provided' do
+      expect(subject.requires?([:foo])).to be(false)
+    end
+
+    context 'lookahead was provided' do
+      let(:lookahead) { double(:Lookahead) }
+
+      before do
+        allow(lookahead).to receive(:selection).with(Symbol).and_return(lookahead)
+      end
+
+      it 'returns false if the path is empty' do
+        expect(subject.requires?([])).to be(false)
+      end
+
+      context 'it selects the field' do
+        before do
+          allow(lookahead).to receive(:selects?).with(Symbol).once.and_return(true)
+        end
+
+        it 'returns true' do
+          expect(subject.requires?(%i[foo bar baz])).to be(true)
+        end
+      end
+
+      context 'it does not select the field' do
+        before do
+          allow(lookahead).to receive(:selects?).with(Symbol).once.and_return(false)
+        end
+
+        it 'returns false' do
+          expect(subject.requires?(%i[foo bar baz])).to be(false)
+        end
+      end
+    end
+  end
+end