diff --git a/spec/lib/mastodon/settings_cli_spec.rb b/spec/lib/mastodon/settings_cli_spec.rb
new file mode 100644
index 00000000000..713cb7e437b
--- /dev/null
+++ b/spec/lib/mastodon/settings_cli_spec.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'mastodon/settings_cli'
+
+RSpec.describe Mastodon::SettingsCLI do
+  describe 'subcommand "registrations"' do
+    let(:cli) { Mastodon::RegistrationsCLI.new }
+
+    before do
+      Setting.registrations_mode = nil
+    end
+
+    describe '#open' do
+      it 'changes "registrations_mode" to "open"' do
+        expect { cli.open }.to change(Setting, :registrations_mode).from(nil).to('open')
+      end
+
+      it 'displays success message' do
+        expect { cli.open }.to output(
+          a_string_including('OK')
+        ).to_stdout
+      end
+    end
+
+    describe '#approved' do
+      it 'changes "registrations_mode" to "approved"' do
+        expect { cli.approved }.to change(Setting, :registrations_mode).from(nil).to('approved')
+      end
+
+      it 'displays success message' do
+        expect { cli.approved }.to output(
+          a_string_including('OK')
+        ).to_stdout
+      end
+
+      context 'with --require-reason' do
+        before do
+          cli.options = { require_reason: true }
+        end
+
+        it 'changes "registrations_mode" to "approved"' do
+          expect { cli.approved }.to change(Setting, :registrations_mode).from(nil).to('approved')
+        end
+
+        it 'sets "require_invite_text" to "true"' do
+          expect { cli.approved }.to change(Setting, :require_invite_text).from(false).to(true)
+        end
+      end
+    end
+
+    describe '#close' do
+      it 'changes "registrations_mode" to "none"' do
+        expect { cli.close }.to change(Setting, :registrations_mode).from(nil).to('none')
+      end
+
+      it 'displays success message' do
+        expect { cli.close }.to output(
+          a_string_including('OK')
+        ).to_stdout
+      end
+    end
+  end
+end