Add unit test for writing to file

Author: AliSoftware

lib/fastlane/plugin/wpmreleasetoolkit/models/app_size_metrics_payload.rb

@@ -53,7 +53,7 @@ def send_metrics(base_url:, api_token:)
         if uri.is_a?(URI::File)
           UI.message("Writing metrics payload to file #{uri.path} (instead of sending it to a server)")
           File.write(uri.path, to_h.to_json)
-          return
+          return 200 # To make it easy at call site to check for pseudo-status code 200 even in non-HTTP cases
         end
 
         UI.message("Sending metrics to #{uri}...")

spec/ios_send_app_size_metrics_spec.rb

@@ -81,4 +81,33 @@ def test_app_size_action(fake_ipa_size:, expected_json:, **other_action_args)
       app_version: '19.8.0.2'
     )
   end
+
+  it 'writes the payload to a file if provided a file:// base URL' do
+    in_tmp_dir do |tmp_dir|
+      # Arrange: Generate a fake `.ipa` file with the expected size
+      ipa_path = File.join(tmp_dir, 'fake.ipa')
+      File.write(ipa_path, SecureRandom.random_bytes(fake_ipa_size))
+      output_path = File.join(tmp_dir, 'payload.json')
+
+      app_thinning_plist_path = File.join(test_data_dir, 'app-thinning.plist')
+      expected_fixture = File.join(test_data_dir, 'app-size-metrics-payload.json')
+      # Parse as Hash then reconvert to JSON, in order to get the 'minified' JSON version
+      expected_json = JSON.parse(File.read(expected_fixture)).to_json
+
+      # Act
+      code = run_described_fastlane_action(
+        api_base_url: File.join('file://localhost/', output_path),
+        app_name: 'wordpress',
+        build_type: 'internal',
+        app_version: '19.8.0.2',
+        ipa_path: ipa_path,
+        app_thinning_plist_path: app_thinning_plist_path
+      )
+
+      # Assert
+      expect(code).to eq(200)
+      expect(File).to exist(output_path)
+      expect(JSON.parse(File.read(output_path))).to eq(JSON.parse(expected_json))
+    end
+  end
 end