--- /dev/null
+<?php
+
+namespace Drupal\block_test\Plugin\Block;
+
+use Drupal\Core\Block\BlockBase;
+
+/**
+ * Provides a context-aware block.
+ *
+ * @Block(
+ * id = "test_context_aware_unsatisfied",
+ * admin_label = @Translation("Test context-aware unsatisfied block"),
+ * context = {
+ * "user" = @ContextDefinition("entity:foobar")
+ * }
+ * )
+ */
+class TestContextAwareUnsatisfiedBlock extends BlockBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function build() {
+ return [
+ '#markup' => 'test',
+ ];
+ }
+
+}