WIP

modules/ui_patterns_field_formatters/tests/src/Kernel/Source/FieldFormatterSourceTest.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\ui_patterns_field_formatters\Kernel\Source;
+
+use Drupal\Tests\ui_patterns\Kernel\SourcePluginsTestBase;
+
+/**
+ * Test FieldFormatterSource.
+ *
+ * @coversDefaultClass \Drupal\ui_patterns_field_formatters\Plugin\UiPatterns\Source\FieldFormatterSource
+ * @group ui_patterns_field_formatters
+ */
+class FieldFormatterSourceTest extends SourcePluginsTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['ui_patterns_field_formatters'];
+
+  /**
+   * Test Field Property Plugin.
+   */
+  public function testPlugin(): void {
+    $testData = self::loadTestDataFixture(__DIR__ . "/../../fixtures/tests.yml");
+    $testSets = $testData->getTestSets();
+    foreach ($testSets as $test_set_name => $test_set) {
+      if (!str_starts_with($test_set_name, 'field_formatter_')) {
+        continue;
+      }
+      $this->runSourcePluginTest($test_set);
+    }
+  }
+
+}

modules/ui_patterns_field_formatters/tests/src/Kernel/Source/FieldLabelSourceTest.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\ui_patterns_field_formatters\Kernel\Source;
+
+use Drupal\Tests\ui_patterns\Kernel\SourcePluginsTestBase;
+
+/**
+ * Test FieldLabelSource.
+ *
+ * @coversDefaultClass \Drupal\ui_patterns_field_formatters\Plugin\UiPatterns\Source\FieldLabelSource
+ * @group ui_patterns_field_formatters
+ */
+class FieldLabelSourceTest extends SourcePluginsTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['ui_patterns_field_formatters'];
+
+  /**
+   * Test Field Property Plugin.
+   */
+  public function testPlugin(): void {
+    $testData = self::loadTestDataFixture(__DIR__ . "/../../fixtures/tests.yml");
+    $testSets = $testData->getTestSets();
+    foreach ($testSets as $test_set_name => $test_set) {
+      if (!str_starts_with($test_set_name, 'field_label_')) {
+        continue;
+      }
+      $this->runSourcePluginTest($test_set);
+    }
+  }
+
+}

modules/ui_patterns_field_formatters/tests/src/fixtures/tests.yml

+---
+field_formatter_default_1:
+  component:
+    component_id: ui_patterns_test:test-component
+    slots:
+      slot:
+        sources:
+          -
+            source_id: field_formatter:node:page:field_text_1
+            source:
+              type: 'string'
+#  contexs:
+    #bundle: page
+    #field_name: 'field_text_1'
+  entity:
+    field_text_1:
+      value: 'value_text_1'
+  output:
+    slots:
+      slot:
+        -
+          rendered_value: "<p>value_text_1</p>"
+          rendered_value_plain: "value_text_1"
+field_formatter_default_2:
+  component:
+    component_id: ui_patterns_test:test-component
+    props:
+      string:
+        source_id: field_formatter:node:page:field_text_1
+        source:
+          type: 'string'
+  output:
+    props:
+      string:
+        rendered_value: "<p>value_text_2</p>"
+        rendered_value_plain: "value_text_2"
+  entity:
+    field_text_1:
+      value: 'value_text_2'
+field_label_default_1:
+  component:
+    component_id: ui_patterns_test:test-component
+    slots:
+      slot:
+        sources:
+          -
+            source_id: field_label
+  contexts:
+    field_name: 'field_text_1'
+  entity: {}
+  output:
+    slots:
+      slot:
+        -
+          rendered_value: "Text (formatted)"
+field_label_default_2:
+  component:
+    component_id: ui_patterns_test:test-component
+    props:
+      string:
+        source_id: field_label
+  contexts:
+    field_name: 'field_text_1'
+  entity: {}
+  output:
+    props:
+      string:
+        value: "Text (formatted)"

tests/src/Traits/RunSourcePluginTestTrait.php

@@ -144,9 +144,12 @@ trait RunSourcePluginTestTrait {
             }
             $plugin = $this->getSourcePluginForPropOrSlot($component, $prop_or_slot_id, $source_to_test, $source_to_test["source_id"], $contexts);
             assertTrue($plugin instanceof SourcePluginBase);
-            $message = sprintf("Test '%s' failed for prop/slot '%s' of component %s with source '%s' ", $test_set["name"] ?? "", $prop_or_slot_id, $component_id, $source_to_test["source_id"]);
-            $prop_value = $plugin->getPropValue();
+            // getPropValue() returns the 'raw' value of the source compatible with the type declared.
+            // getValue() returns the value of the source converted to the type definition.
+            $prop_value = $plugin->getValue($plugin->getPropDefinition()["ui_patterns"]["type_definition"]);
+            $message = sprintf("Test '%s' failed for prop/slot '%s' of component %s with source '%s'", $test_set["name"] ?? "", $prop_or_slot_id, $component_id, $source_to_test["source_id"]);
             $this->assertExpectedOutput($expected_outputs_here[$index], $prop_value, $message);
+
           }
         }
       }

tests/src/Traits/TestDataTrait.php

@@ -4,7 +4,9 @@ declare(strict_types=1);
 
 namespace Drupal\Tests\ui_patterns\Traits;
 
+use Drupal\Component\Render\MarkupInterface;
 use Drupal\Component\Serialization\Yaml;
+use Drupal\Component\Utility\Xss;
 
 /**
  * Trait to read fixtures that describe component test situations.
@@ -51,20 +53,54 @@ trait TestDataTrait {
    * @throws \RuntimeException
    */
   protected function assertExpectedOutput(array $expected_result, mixed $result, string $message = ''): void {
+    $assert_done = FALSE;
     if (isset($expected_result['value'])) {
-      $this->assertContains($expected_result['value'], [$result], $message);
+      $this->assertContains($expected_result['value'], [$result], sprintf("%s: '%s'", $message, print_r($result, TRUE)));
+      $assert_done = TRUE;
     }
-    elseif (isset($expected_result['same'])) {
+    if (isset($expected_result['value_normalized'])) {
+      $normalized_value = self::normalizeMarkupString($result);
+      $this->assertContains($expected_result['value'], [$normalized_value], sprintf("%s: '%s'", $message, $normalized_value));
+      $assert_done = TRUE;
+    }
+    if (isset($expected_result['same'])) {
       $this->assertSame($expected_result['same'], $result, $message);
+      $assert_done = TRUE;
     }
-    elseif (isset($expected_result['regEx'])) {
+    if (isset($expected_result['regEx'])) {
       $this->assertTrue(preg_match($expected_result['regEx'], $result) === 1, $message);
+      $assert_done = TRUE;
+    }
+    if (isset($expected_result['rendered_value']) || isset($expected_result['rendered_value_plain']) || isset($expected_result['rendered_value_normalized'])) {
+      $rendered = \Drupal::service('renderer')->renderRoot($result);
+      // $rendered = is_array($result) ? \Drupal::service('renderer')->renderRoot($result) : $result;
+      if ($rendered instanceof MarkupInterface) {
+        $rendered = "" . $rendered;
+      }
+      $normalized_rendered = self::normalizeMarkupString($rendered);
+      if (isset($expected_result['rendered_value'])) {
+        $this->assertContains($expected_result['rendered_value'], [$normalized_rendered], sprintf("%s: '%s'", $message, $normalized_rendered));
+      }
+      if (isset($expected_result['rendered_value_plain'])) {
+        $rendered_plain = Xss::filter($normalized_rendered);
+        $this->assertContains($expected_result['rendered_value_plain'], [$rendered_plain], sprintf("%s: '%s'", $message, $rendered_plain));
+      }
+      $assert_done = TRUE;
     }
-    else {
+    if (!$assert_done) {
       throw new \RuntimeException(sprintf('Missing "value" or "regEx" in expected result %s', print_r($expected_result, TRUE)));
     }
   }
 
+  /**
+   * Normalize a string of markup for comparison.
+   */
+  protected static function normalizeMarkupString(string $markup): string {
+    $markup = preg_replace('/\s*(<|>)\s*/', '$1', $markup);
+    $markup = trim($markup);
+    return $markup;
+  }
+
   /**
    * Loads test dataset fixture.
    */