deno - 在完成测试用例之前关闭从 Deno API 返回的开放资源句柄

Question

我收到此错误消息:

Make sure to close all open resource handles returned from Deno APIs before 
finishing test case.

当我运行此 Deno 测试函数时:

import { assertEquals } from "https://deno.land/std/testing/asserts.ts";

Deno.test("fetch example", async function (): Promise<void> {
    await fetch("http://www.google.com.br").then(data => {
        console.log('completed')
    });
    assertEquals("world", "world");
});

我用来运行它的命令是:

deno test --allow-net

我查看了documentation但我没能找到解决问题的方法。

这是完整的错误堆栈:

$ deno test --allow-net
Compile file:///<my_path>/isolated_test.ts
running 1 tests
test fetch example ... completed
FAILED (199ms)

failures:

fetch example
AssertionError: Test case is leaking resources.
Before: {
  "0": "stdin",
  "1": "stdout",
  "2": "stderr"
}
After: {
  "0": "stdin",
  "1": "stdout",
  "2": "stderr",
  "3": "httpBody"
}

Make sure to close all open resource handles returned from Deno APIs before 
finishing test case.
    at Object.assert ($deno$/util.ts:33:11)
    at Object.resourceSanitizer [as fn] ($deno$/testing.ts:81:5)
    at async TestApi.[Symbol.asyncIterator] ($deno$/testing.ts:264:11)
    at async Object.runTests ($deno$/testing.ts:346:20)

failures:

        fetch example

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out (199ms)

我的 deno 版本

$ deno --version
deno 1.0.2
v8 8.4.300
typescript 3.9.2

Answer 1

Deno 测试检查测试期间未正确关闭的资源句柄。

为了修复您的测试，您需要使用响应正文，因为内部使用资源句柄。一种简单的方法是调用 .text 或任何其他方法来使用正文:arrayBuffer、json、formData， Blob

Deno.test("fetch example", async function (): Promise<void> {
    const res = await fetch("http://www.google.com.br")
    await res.text(); // Consume the body so the file handle is closed
    assertEquals("world", "world");
});

您可以看到资源句柄之一是httpBody:

After: {
  "0": "stdin",
  "1": "stdout",
  "2": "stderr",
  "3": "httpBody"
}

目前，由于 Deno 的 fetch 不支持 AbortController，因此无法忽略正文。

仅当状态代码为 301、302、303、307、308 之一时，Deno 才会自动关闭资源句柄

更新

从 Deno 1.0.3 开始，Response.body 现在是一个 ReadableStream ( PR #5787 ) 并且可以关闭资源句柄调用 `res.body.cancel();

Deno.test("fetch example", async function (): Promise<void> {
     const res = await fetch("http://www.google.com.br")
     await res.body.cancel(); // Cancel the body so the file handle is closed
     assertEquals("world", "world");
});