Add ReferenceMockRegistry

spec/spectator/mocks/reference_mock_registry_spec.cr

@@ -0,0 +1,23 @@
+require "../../spec_helper"
+
+Spectator.describe Spectator::ReferenceMockRegistry do
+  subject(registry) { described_class.new }
+  let(stub) { Spectator::ValueStub.new(:test, 42) }
+
+  it "initially has no stubs" do
+    obj = "foobar"
+    expect(registry[obj]).to be_empty
+  end
+
+  it "stores stubs for an object" do
+    obj = "foobar"
+    expect { registry[obj] << stub }.to change { registry[obj] }.from([] of Spectator::Stub).to([stub])
+  end
+
+  it "isolates stubs between different objects" do
+    obj1 = "foo"
+    obj2 = "bar"
+    registry[obj2] << Spectator::ValueStub.new(:obj2, 42)
+    expect { registry[obj1] << stub }.to_not change { registry[obj2] }
+  end
+end