feat: add task card block example

block-kit/README.md

@@ -18,5 +18,6 @@ Read the [docs](https://docs.slack.dev/block-kit/) to learn concepts behind thes
 - **[Markdown](https://docs.slack.dev/reference/block-kit/blocks/markdown-block)**: Displays formatted markdown. [Implementation](./src/main/java/blocks/Markdown.java).
 - **[Rich text](https://docs.slack.dev/reference/block-kit/blocks/rich-text-block)**: Displays formatted, structured representation of text. [Implementation](./src/main/java/blocks/RichText.java).
 - **[Section](https://docs.slack.dev/reference/block-kit/blocks/section-block)**: Displays text, possibly alongside elements. [Implementation](./src/main/java/blocks/Section.java).
+- **[Task card](https://docs.slack.dev/reference/block-kit/blocks/task-card-block)**: Displays a single task, representing a single action. [Implementation](./src/main/java/blocks/TaskCard.java).
 - **[Video](https://docs.slack.dev/reference/block-kit/blocks/video-block)**: Displays an embedded video player. [Implementation](./src/main/java/blocks/Video.java).
 

block-kit/src/main/java/blocks/TaskCard.java

@@ -0,0 +1,40 @@
+package blocks;
+
+import com.slack.api.model.block.Blocks;
+import com.slack.api.model.block.RichTextBlock;
+import com.slack.api.model.block.TaskCardBlock;
+import com.slack.api.model.block.element.RichTextSectionElement;
+import com.slack.api.model.block.element.UrlSourceElement;
+import java.util.List;
+
+/**
+ * Displays a single task, representing a single action.
+ * {@link https://docs.slack.dev/reference/block-kit/blocks/task-card-block/}
+ */
+public class TaskCard {
+    /**
+     * A task card with output and sources.
+     */
+    public static TaskCardBlock example01() {
+        TaskCardBlock block = Blocks.taskCard(t -> t.taskId("task_1")
+                .title("Fetching weather data")
+                .status("in_progress")
+                .output(RichTextBlock.builder()
+                        .elements(List.of(RichTextSectionElement.builder()
+                                .elements(List.of(RichTextSectionElement.Text.builder()
+                                        .text("Found weather data for Chicago from 2 sources")
+                                        .build()))
+                                .build()))
+                        .build())
+                .sources(List.of(
+                        UrlSourceElement.builder()
+                                .url("https://weather.com/")
+                                .text("weather.com")
+                                .build(),
+                        UrlSourceElement.builder()
+                                .url("https://www.accuweather.com/")
+                                .text("accuweather.com")
+                                .build())));
+        return block;
+    }
+}

block-kit/src/test/java/blocks/TaskCardTest.java

@@ -0,0 +1,51 @@
+package blocks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.google.gson.JsonParser;
+import com.slack.api.model.block.TaskCardBlock;
+import com.slack.api.util.json.GsonFactory;
+import org.junit.jupiter.api.Test;
+
+public class TaskCardTest {
+    @Test
+    public void testExample01() {
+        TaskCardBlock block = TaskCard.example01();
+        String actual = GsonFactory.createSnakeCase().toJson(block);
+        String expected = """
+            {
+              "type": "task_card",
+              "task_id": "task_1",
+              "title": "Fetching weather data",
+              "status": "in_progress",
+              "output": {
+                "type": "rich_text",
+                "elements": [
+                  {
+                    "type": "rich_text_section",
+                    "elements": [
+                      {
+                        "type": "text",
+                        "text": "Found weather data for Chicago from 2 sources"
+                      }
+                    ]
+                  }
+                ]
+              },
+              "sources": [
+                {
+                  "type": "url",
+                  "url": "https://weather.com/",
+                  "text": "weather.com"
+                },
+                {
+                  "type": "url",
+                  "url": "https://www.accuweather.com/",
+                  "text": "accuweather.com"
+                }
+              ]
+            }
+            """;
+        assertEquals(JsonParser.parseString(expected), JsonParser.parseString(actual));
+    }
+}