refactor: replace implicit tuple protocol in ScreenshotAssertion

ScreenshotMatcher now constructs ScreenshotAssertion directly instead
of passing [caller, name, compare] array to ScreenshotAssertion.from.
Removes undocumented array protocol that was easy to break.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pftg

lib/capybara/screenshot/diff/reporters/default.rb

@@ -8,7 +8,7 @@ class Default
       def initialize(difference)
         @difference = difference
 
-        screenshot_format = difference.comparison.options[:screenshot_format] || comparison.new_image_path.extname.delete_prefix(".").then { |ext| ext.empty? ? "png" : ext }
+        screenshot_format = difference.comparison.options[:screenshot_format] || comparison.new_image_path.extname.delete_prefix(".").presence || "png"
         @annotated_image_path = comparison.new_image_path.sub_ext(".diff.#{screenshot_format}")
         @annotated_base_image_path = comparison.base_image_path.sub_ext(".diff.#{screenshot_format}")
         @heatmap_diff_path = comparison.new_image_path.sub_ext(".heatmap.diff.#{screenshot_format}")

lib/capybara/screenshot/diff/screenshot_matcher.rb

@@ -89,11 +89,10 @@ def capture_screenshot(capture_options, comparison_options)
         end
 
         def create_screenshot_assertion(skip_stack_frames, comparison_options)
-          CapybaraScreenshotDiff::ScreenshotAssertion.from([
-            caller(skip_stack_frames + 1),
-            screenshot_full_name,
-            ImageCompare.new(@snapshot.path, @snapshot.base_path, comparison_options)
-          ])
+          assertion = CapybaraScreenshotDiff::ScreenshotAssertion.new(screenshot_full_name)
+          assertion.caller = caller(skip_stack_frames + 1)
+          assertion.compare = ImageCompare.new(@snapshot.path, @snapshot.base_path, comparison_options)
+          assertion
         end
 
         def extract_capture_and_comparison_options!(driver_options = {})

lib/capybara_screenshot_diff/screenshot_assertion.rb

@@ -7,21 +7,9 @@ class ScreenshotAssertion
     attr_reader :name, :args
     attr_accessor :compare, :caller
 
-    def initialize(name, **args, &block)
+    def initialize(name, **args)
       @name = name
       @args = args
-
-      yield(self) if block_given?
-    end
-
-    def self.from(screenshot_job)
-      return screenshot_job if screenshot_job.is_a?(ScreenshotAssertion)
-
-      caller, name, compare = screenshot_job
-      ScreenshotAssertion.new(name).tap do |assertion|
-        assertion.caller = caller
-        assertion.compare = compare
-      end
     end
 
     def validate
@@ -89,8 +77,7 @@ def initialize
     end
 
     def add_assertion(assertion)
-      assertion = ScreenshotAssertion.from(assertion)
-      return unless assertion.compare
+      return unless assertion&.compare
 
       @assertions.push(assertion)
 

test/unit/diff_test.rb

@@ -155,7 +155,9 @@ def _test_sample_screenshot_error
           mock.expect(:base_image_path, Pathname.new("screenshot.base.png"))
           mock.expect(:error_message, "expected error message")
 
-          assertion = CapybaraScreenshotDiff::ScreenshotAssertion.from([["my_test.rb:42"], "sample_screenshot", mock])
+          assertion = CapybaraScreenshotDiff::ScreenshotAssertion.new("sample_screenshot")
+          assertion.caller = ["my_test.rb:42"]
+          assertion.compare = mock
           CapybaraScreenshotDiff.add_assertion(assertion)
 
           assert true
@@ -189,7 +191,9 @@ def _test_sample_screenshot_error
           comparison.expect(:base_image_path, Pathname.new("screenshot.base.png"))
           comparison.expect(:error_message, "expected error message for non minitest")
 
-          assertion = CapybaraScreenshotDiff::ScreenshotAssertion.from([["my_test.rb:42"], "sample_screenshot", comparison])
+          assertion = CapybaraScreenshotDiff::ScreenshotAssertion.new("sample_screenshot")
+          assertion.caller = ["my_test.rb:42"]
+          assertion.compare = comparison
           CapybaraScreenshotDiff.add_assertion(assertion)
         end
       end

test/unit/dsl_test.rb

@@ -100,6 +100,21 @@ def assert_no_screenshot_jobs_scheduled
       end
     end
 
+    test "#assert_no_screenshot_changes reports caller from test method" do
+      Capybara::Screenshot::Diff::Vcs.stub(:checkout_vcs, true) do
+        assert_no_screenshot_jobs_scheduled
+
+        snap = create_snapshot_for(:a, :c)
+
+        assert_no_screenshot_changes(snap.full_name)
+        assert_equal 1, CapybaraScreenshotDiff.assertions.size
+        assert_match(
+          %r{/dsl_test.rb},
+          CapybaraScreenshotDiff.assertions[0].caller.first
+        )
+      end
+    end
+
     test "#screenshot with delayed: false raises error when images differ" do
       Capybara::Screenshot::Diff::Vcs.stub(:checkout_vcs, true) do
         Capybara::Screenshot::Diff.stub(:delayed, false) do