Added replace tool ability to replace more than 1 occurrence (#669)

Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>

packages/core/src/tools/edit.test.ts

@@ -484,6 +484,49 @@ describe('EditTool', () => {
       );
     });
 
+    it('should successfully replace multiple occurrences when expected_replacements specified', async () => {
+      fs.writeFileSync(filePath, 'old text old text old text', 'utf8');
+      const params: EditToolParams = {
+        file_path: filePath,
+        old_string: 'old',
+        new_string: 'new',
+        expected_replacements: 3,
+      };
+
+      // Simulate confirmation by setting shouldAlwaysEdit
+      (tool as any).shouldAlwaysEdit = true;
+
+      const result = await tool.execute(params, new AbortController().signal);
+
+      (tool as any).shouldAlwaysEdit = false; // Reset for other tests
+
+      expect(result.llmContent).toMatch(/Successfully modified file/);
+      expect(fs.readFileSync(filePath, 'utf8')).toBe(
+        'new text new text new text',
+      );
+      const display = result.returnDisplay as FileDiff;
+      expect(display.fileDiff).toMatch(/old text old text old text/);
+      expect(display.fileDiff).toMatch(/new text new text new text/);
+      expect(display.fileName).toBe(testFile);
+    });
+
+    it('should return error if expected_replacements does not match actual occurrences', async () => {
+      fs.writeFileSync(filePath, 'old text old text', 'utf8');
+      const params: EditToolParams = {
+        file_path: filePath,
+        old_string: 'old',
+        new_string: 'new',
+        expected_replacements: 3, // Expecting 3 but only 2 exist
+      };
+      const result = await tool.execute(params, new AbortController().signal);
+      expect(result.llmContent).toMatch(
+        /Expected 3 occurrences but found 2 for old_string in file/,
+      );
+      expect(result.returnDisplay).toMatch(
+        /Failed to edit, expected 3 occurrence\(s\) but found 2/,
+      );
+    });
+
     it('should return error if trying to create a file that already exists (empty old_string)', async () => {
       fs.writeFileSync(filePath, 'Existing content', 'utf8');
       const params: EditToolParams = {