Clear Firestore database after testing

I am running Android UI tests. I use a separate Firestore DB for testing. I want to delete all documents after a test finishes. This curl command works.

curl -v -X DELETE "http://127.0.0.1:8080/emulator/v1/projects/test/databases/(default)/documents"

I want to use this in a method in my test class.

class MainActivityTest {
    @Rule
    // rule goes here

    @BeforeClass
    public static void setUp() {
        String androidLocalHost = "10.0.2.2";
        int portNumber = 8080;
        FirebaseFirestore.getInstance().useEmulator(androidLocalHost, portNumber);
        Log.d("DBT", "Connected to local Firestore");
    }
    
    @After
    public void tearDown() {
        String projectId = "test";
        URL url = null;
        try {
            url = new URL("http://10.0.2.2:8080/emulator/v1/projects/" + projectId + "/databases/(default)/documents");
        } catch (MalformedURLException exception) {
            Log.e("URLError", Objects.requireNonNull(exception.getMessage()));
        }
        HttpURLConnection urlConnection = null;
        Log.d("TeardownURL", "Connecting to: " + url.toString());
        try {
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("DELETE");
            int response = urlConnection.getResponseCode();
            String msg = urlConnection.getResponseMessage();
            Log.i("ResponseCode", "[Response Code: " + response + "] msg: " + msg);
        } catch (IOException exception) {
            Log.e("IOError", Objects.requireNonNull(exception.getMessage()));
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
        }
    }
}

I added network_security_config.xml to allow cleartext and include the host 10.0.2.2 and updated the manifest file accordingly.

However, I get 404 Not found (in ResponseCode log).

My curl command works fine. The only difference is curl uses localhost/127.0.0.1. Since this is in Android studio, I use 10.0.2.2.

After a couple of rounds of prompting with Gemini, I found the solution. I needed to include this line after the urlConnection.requestMethod() call.

urlConnection.setRequestProperty("Content-Type", "application/json");

Now, I am getting the 200 OK response code/msg.