Cobble a passing mspec test together

This is very much in the PoC state

.github/workflows/test.yml

@@ -111,3 +111,13 @@ jobs:
           SPEC_TIMEOUT: 480
           SOME_TESTS: true
         run: rake docker_test_asan
+  mspec:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: install ruby
+        run: sudo apt-get install -y ruby ruby-bundler
+      - name: install rspec
+        run: cd test/mspec && sudo bundle install
+      - name: run very limited hacked mspec test
+        run: cd test/mspec && bundle exec rspec -I. matchers/be_an_instance_of_spec.rb

test/mspec/Gemfile

@@ -0,0 +1,4 @@
+source 'https://rubygems.org'
+
+gem "rake", "~> 12.3"
+gem "rspec", "~> 3.0"

test/mspec/Gemfile.lock

@@ -0,0 +1,26 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.4.4)
+    rake (12.3.3)
+    rspec (3.10.0)
+      rspec-core (~> 3.10.0)
+      rspec-expectations (~> 3.10.0)
+      rspec-mocks (~> 3.10.0)
+    rspec-core (3.10.1)
+      rspec-support (~> 3.10.0)
+    rspec-expectations (3.10.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-mocks (3.10.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-support (3.10.2)
+
+PLATFORMS
+  java
+  ruby
+
+DEPENDENCIES
+  rake (~> 12.3)
+  rspec (~> 3.0)

test/mspec/helpers/fixture_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
-require 'mspec/guards'
-require 'mspec/helpers'
+#require 'mspec/guards'
+#require 'mspec/helpers'
 
 RSpec.describe Object, "#fixture" do
   before :each do

test/mspec/matchers/be_an_instance_of_spec.rb

@@ -1,6 +1,23 @@
 require 'spec_helper'
-require 'mspec/expectations/expectations'
-require 'mspec/matchers'
+#require 'mspec/expectations/expectations'
+#require 'mspec/matchers'
+class BeAnInstanceOfMatcher
+  attr_reader :failure_message, :negative_failure_message
+
+  def initialize(klass)
+    @wrapped = BeInstanceOfExpectation.new(klass)
+    @klass = klass
+  end
+
+  def matches?(subject)
+    @wrapped.match(subject)
+    true
+  rescue SpecFailedException => e
+    @failure_message = ["Expected #{subject.inspect} (#{subject.class})", "to be an instance of #{@klass}"]
+    @negative_failure_message = ["Expected #{subject.inspect} (#{subject.class})", "not to be an instance of #{@klass}"]
+    nil
+  end
+end
 
 module BeAnInOfSpecs
   class A

test/mspec/spec_helper.rb

@@ -3,7 +3,7 @@
   config.raise_errors_for_deprecations!
 end
 
-require 'mspec'
+require_relative '../spec_helper'
 
 # Remove this when MRI has intelligent warnings
 $VERBOSE = nil unless $VERBOSE
@@ -63,7 +63,7 @@ def ensure_mspec_method(method)
 end
 
 PublicMSpecMatchers = Class.new {
-  include MSpecMatchers
+  # include MSpecMatchers
   public :raise_error
 }.new