feat(backup-monitor): implement WebhookClient with injected HTTP adapter and tests

scripts/notify_backup.rb

@@ -86,6 +86,32 @@ class PayloadBuilder
 end
 
 class WebhookClient
+  def initialize(base_url:, auth_token:, http_adapter: Net::HTTP)
+    @base_url     = base_url
+    @auth_token   = auth_token
+    @http_adapter = http_adapter
+  end
+
+  def post(payload)
+    uri     = URI("#{@base_url}/webhook/backup-notify")
+    request = build_request(uri, payload)
+
+    response = @http_adapter.start(uri.hostname, uri.port, use_ssl: uri.scheme == 'https') do |http|
+      http.request(request)
+    end
+
+    raise "HTTP #{response.code}: #{response.body}" unless response.is_a?(Net::HTTPSuccess)
+  end
+
+  private
+
+  def build_request(uri, payload)
+    req = Net::HTTP::Post.new(uri)
+    req['Content-Type']  = 'application/json'
+    req['Authorization'] = "Bearer #{@auth_token}"
+    req.body             = JSON.generate(payload)
+    req
+  end
 end
 
 class BackupNotifier

scripts/notify_backup_test.rb

@@ -80,3 +80,59 @@ class PayloadBuilderTest < Minitest::Test
     end
   end
 end
+
+# Stub HTTP adapter for WebhookClient tests — replaces Net::HTTP entirely.
+# Sandi Metz: test the interface, inject the dependency, don't touch globals.
+class FakeHttpAdapter
+  def initialize(response)
+    @response = response
+  end
+
+  def start(_host, _port, use_ssl: false)
+    yield FakeHttpSession.new(@response)
+  end
+end
+
+class FakeHttpSession
+  def initialize(response)
+    @response = response
+  end
+
+  def request(_req)
+    @response
+  end
+end
+
+class WebhookClientTest < Minitest::Test
+  def make_success_response
+    res = Net::HTTPSuccess.new('1.1', '200', 'OK')
+    res.instance_variable_set(:@read, true)
+    res
+  end
+
+  def make_error_response
+    res = Net::HTTPServerError.new('1.1', '500', 'Internal Server Error')
+    res.instance_variable_set(:@body, 'something broke')
+    res.instance_variable_set(:@read, true)
+    res
+  end
+
+  def make_client(response)
+    WebhookClient.new(
+      base_url:     'https://n8n.example.com',
+      auth_token:   'test-token',
+      http_adapter: FakeHttpAdapter.new(response)
+    )
+  end
+
+  def test_post_succeeds_on_200
+    client = make_client(make_success_response)
+    client.post({ machine: 'desktop', status: 'success' })  # no error raised
+  end
+
+  def test_post_raises_on_500
+    client = make_client(make_error_response)
+    err = assert_raises(RuntimeError) { client.post({}) }
+    assert_match(/HTTP 500/, err.message)
+  end
+end