1 files changed, 113 insertions, 0 deletions
diff --git a/spec/support/shared_examples/models/atomic_internal_id_shared_examples.rb b/spec/support/shared_examples/models/atomic_internal_id_shared_examples.rb
new file mode 100644
index 00000000000..a248f60d23e
--- /dev/null
+++ b/spec/support/shared_examples/models/atomic_internal_id_shared_examples.rb
@@ -0,0 +1,113 @@
+require 'spec_helper'
+
+shared_examples_for 'AtomicInternalId' do |validate_presence: true|
+  describe '.has_internal_id' do
+    describe 'Module inclusion' do
+      subject { described_class }
+
+      it { is_expected.to include_module(AtomicInternalId) }
+    end
+
+    describe 'Validation' do
+      before do
+        allow_any_instance_of(described_class).to receive(:"ensure_#{scope}_#{internal_id_attribute}!")
+
+        instance.valid?
+      end
+
+      context 'when presence validation is required' do
+        before do
+          skip unless validate_presence
+        end
+
+        it 'validates presence' do
+          expect(instance.errors[internal_id_attribute]).to include("can't be blank")
+        end
+      end
+
+      context 'when presence validation is not required' do
+        before do
+          skip if validate_presence
+        end
+
+        it 'does not validate presence' do
+          expect(instance.errors[internal_id_attribute]).to be_empty
+        end
+      end
+    end
+
+    describe 'Creating an instance' do
+      subject { instance.save! }
+
+      it 'saves a new instance properly' do
+        expect { subject }.not_to raise_error
+      end
+    end
+
+    describe 'internal id generation' do
+      subject { instance.save! }
+
+      it 'calls InternalId.generate_next and sets internal id attribute' do
+        iid = rand(1..1000)
+
+        expect(InternalId).to receive(:generate_next).with(instance, scope_attrs, usage, any_args).and_return(iid)
+        subject
+        expect(read_internal_id).to eq(iid)
+      end
+
+      it 'does not overwrite an existing internal id' do
+        write_internal_id(4711)
+
+        expect { subject }.not_to change { read_internal_id }
+      end
+
+      context 'when the instance has an internal ID set' do
+        let(:internal_id) { 9001 }
+
+        it 'calls InternalId.update_last_value and sets the `last_value` to that of the instance' do
+          write_internal_id(internal_id)
+
+          expect(InternalId)
+            .to receive(:track_greatest)
+            .with(instance, scope_attrs, usage, internal_id, any_args)
+            .and_return(internal_id)
+          subject
+        end
+      end
+    end
+
+    describe "#reset_scope_internal_id_attribute" do
+      it 'rewinds the allocated IID' do
+        expect { ensure_scope_attribute! }.not_to raise_error
+        expect(read_internal_id).not_to be_nil
+
+        expect(reset_scope_attribute).to be_nil
+        expect(read_internal_id).to be_nil
+      end
+
+      it 'allocates the same IID' do
+        internal_id = ensure_scope_attribute!
+        reset_scope_attribute
+        expect(read_internal_id).to be_nil
+
+        expect(ensure_scope_attribute!).to eq(internal_id)
+      end
+    end
+
+    def ensure_scope_attribute!
+      instance.public_send(:"ensure_#{scope}_#{internal_id_attribute}!")
+    end
+
+    def reset_scope_attribute
+      instance.public_send(:"reset_#{scope}_#{internal_id_attribute}")
+    end
+
+    def read_internal_id
+      instance.public_send(internal_id_attribute)
+    end
+
+    def write_internal_id(value)
+      instance.public_send(:"#{internal_id_attribute}=", value)
+    end
+  end
+end