feat: 实现 PromptBuilder 段落构建器

tests/core/prompt-builder.test.ts

@@ -0,0 +1,78 @@
+import { describe, it, expect } from "bun:test";
+import { PromptBuilder } from "../../src/core/prompt-builder";
+
+describe("PromptBuilder", () => {
+  it("空 builder build 返回空字符串", () => {
+    const builder = new PromptBuilder();
+    expect(builder.build()).toBe("");
+  });
+
+  it("单段输出", () => {
+    const result = new PromptBuilder().head("# 标题").build();
+    expect(result).toBe("# 标题");
+  });
+
+  it("多段按序渲染", () => {
+    const result = new PromptBuilder()
+      .head("# 阶段")
+      .context("状态信息")
+      .prompt("核心引导")
+      .guide("操作指令")
+      .warn("警告信息")
+      .build();
+
+    const headPos = result.indexOf("# 阶段");
+    const contextPos = result.indexOf("状态信息");
+    const promptPos = result.indexOf("核心引导");
+    const guidePos = result.indexOf("操作指令");
+    const warnPos = result.indexOf("警告信息");
+
+    expect(headPos).toBeLessThan(contextPos);
+    expect(contextPos).toBeLessThan(promptPos);
+    expect(promptPos).toBeLessThan(guidePos);
+    expect(guidePos).toBeLessThan(warnPos);
+  });
+
+  it("空段跳过", () => {
+    const result = new PromptBuilder().head("# 标题").prompt("内容").guide("指引").build();
+    expect(result).toContain("# 标题");
+    expect(result).toContain("内容");
+    expect(result).toContain("指引");
+  });
+
+  it("同 kind 多次追加拼接", () => {
+    const result = new PromptBuilder()
+      .head("# 阶段")
+      .context("信息一")
+      .context("信息二")
+      .prompt("prompt")
+      .build();
+    expect(result).toContain("信息一\n\n信息二");
+  });
+
+  it("head 重复设值覆盖", () => {
+    const result = new PromptBuilder().head("# 旧标题").head("# 新标题").build();
+    expect(result).toBe("# 新标题");
+    expect(result).not.toContain("旧标题");
+  });
+
+  it("prompt 重复设值覆盖", () => {
+    const result = new PromptBuilder().prompt("旧 prompt").prompt("新 prompt").build();
+    expect(result).toContain("新 prompt");
+    expect(result).not.toContain("旧 prompt");
+  });
+
+  it("空字符串段被跳过", () => {
+    const result = new PromptBuilder().head("# 标题").context("").prompt("内容").build();
+    expect(result).toBe("# 标题\n\n内容");
+  });
+
+  it("链式调用返回 this", () => {
+    const builder = new PromptBuilder();
+    expect(builder.head("x")).toBe(builder);
+    expect(builder.context("x")).toBe(builder);
+    expect(builder.prompt("x")).toBe(builder);
+    expect(builder.guide("x")).toBe(builder);
+    expect(builder.warn("x")).toBe(builder);
+  });
+});