Document current behaviour more thoroughly before altering it

#1108

Co-authored-by: Szymon Fiedler <[email protected]>

Author: mostlyobvious

Diff for: ruby_event_store-active_record/spec/transactions_spec.rb

@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+require "ruby_event_store"
+require "ruby_event_store/spec/event_repository_lint"
+
+module RubyEventStore
+  module ActiveRecord
+    ::RSpec.describe EventRepository do
+      helper = SpecHelper.new
+      mk_repository = -> { EventRepository.new(serializer: helper.serializer) }
+
+      let(:repository) { mk_repository.call }
+      let(:specification) do
+        Specification.new(
+          SpecificationReader.new(repository, Mappers::Default.new)
+        )
+      end
+
+      let(:stream) { Stream.new(SecureRandom.uuid) }
+      let(:foo) { SRecord.new(event_id: SecureRandom.uuid) }
+      let(:bar) { SRecord.new(event_id: SecureRandom.uuid) }
+      let(:baz) { SRecord.new(event_id: SecureRandom.uuid) }
+      let(:global_to_a) { repository.read(specification.result).to_a }
+      let(:stream_to_a) do
+        repository.read(specification.stream(stream.name).result).to_a
+      end
+
+      around(:each) { |example| helper.run_lifecycle { example.run } }
+
+      around(:each) do |example|
+        ::ActiveRecord::Base.logger =
+          Logger
+            .new(STDOUT)
+            .tap do |l|
+              l.formatter =
+                proc { |severity, datetime, progname, msg| "#{msg}\n" }
+            end
+        example.run
+        ::ActiveRecord::Base.logger = nil
+      end
+
+      specify "no application transaction, event_id conflict" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.any)
+
+        expect do
+          repository.append_to_stream([bar], stream, ExpectedVersion.any)
+          repository.append_to_stream([foo], stream, ExpectedVersion.any)
+        end.to raise_error(EventDuplicatedInStream)
+
+        expect(global_to_a).to eq([foo, bar])
+        expect(stream_to_a).to eq([foo, bar])
+      end
+
+      specify "no application transaction, expected_version conflict" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.none)
+
+        expect do
+          repository.append_to_stream([bar], stream, ExpectedVersion.any)
+          repository.append_to_stream([baz], stream, ExpectedVersion.none)
+        end.to raise_error(WrongExpectedEventVersion)
+
+        expect(global_to_a).to eq([foo, bar])
+        expect(stream_to_a).to eq([foo, bar])
+      end
+
+      specify "application transaction, event_id conflict" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.any)
+
+        expect do
+          helper.with_transaction do
+            repository.append_to_stream([bar], stream, ExpectedVersion.any)
+            repository.append_to_stream([foo], stream, ExpectedVersion.any)
+          end
+        end.to raise_error(EventDuplicatedInStream)
+
+        expect(global_to_a).to eq([foo])
+        expect(stream_to_a).to eq([foo])
+      end
+
+      specify "application transaction, expected_version conflict" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.none)
+
+        expect do
+          helper.with_transaction do
+            repository.append_to_stream([bar], stream, ExpectedVersion.any)
+            repository.append_to_stream([baz], stream, ExpectedVersion.none)
+          end
+        end.to raise_error(WrongExpectedEventVersion)
+
+        expect(global_to_a).to eq([foo])
+        expect(stream_to_a).to eq([foo])
+      end
+
+      specify "application transaction, event_id conflict — rescued" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.any)
+
+        helper.with_transaction do
+          begin
+            repository.append_to_stream([bar], stream, ExpectedVersion.any)
+            repository.append_to_stream([foo], stream, ExpectedVersion.any)
+          rescue EventDuplicatedInStream
+          end
+        end
+
+        expect(global_to_a).to eq([foo, bar])
+        expect(stream_to_a).to eq([foo, bar])
+      end
+
+      specify "application transaction, expected_version conflict — rescued" do
+        repository.append_to_stream([foo], stream, ExpectedVersion.none)
+
+        helper.with_transaction do
+          begin
+            repository.append_to_stream([bar], stream, ExpectedVersion.any)
+            repository.append_to_stream([baz], stream, ExpectedVersion.none)
+          rescue WrongExpectedEventVersion
+          end
+        end
+
+        expect(global_to_a).to eq([foo, bar])
+        expect(stream_to_a).to eq([foo, bar])
+      end
+    end
+  end
+end