feat: add more tests for tool built-ins (#5)

src/tests/tools/multiedit.test.ts

@@ -0,0 +1,43 @@
+import { afterEach, describe, expect, test } from "bun:test";
+import { readFileSync } from "node:fs";
+import { multi_edit } from "../../tools/impl/MultiEdit";
+import { TestDirectory } from "../helpers/testFs";
+
+describe("MultiEdit tool", () => {
+  let testDir: TestDirectory;
+
+  afterEach(() => {
+    testDir?.cleanup();
+  });
+
+  test("applies multiple edits to a file", async () => {
+    testDir = new TestDirectory();
+    const file = testDir.createFile("test.txt", "foo bar baz");
+
+    await multi_edit({
+      file_path: file,
+      edits: [
+        { old_string: "foo", new_string: "FOO" },
+        { old_string: "bar", new_string: "BAR" },
+      ],
+    });
+
+    expect(readFileSync(file, "utf-8")).toBe("FOO BAR baz");
+  });
+
+  test("applies edits sequentially", async () => {
+    testDir = new TestDirectory();
+    const file = testDir.createFile("test.txt", "aaa bbb");
+
+    const result = await multi_edit({
+      file_path: file,
+      edits: [
+        { old_string: "aaa", new_string: "xxx" },
+        { old_string: "bbb", new_string: "yyy" },
+      ],
+    });
+
+    expect(readFileSync(file, "utf-8")).toBe("xxx yyy");
+    expect(result.edits_applied).toBe(2);
+  });
+});