Controller unit test failure when the request body is empty and is read directly

[aentwist]

Implementing complete GraphQL support involves reading the request body and considering it as the query for one special case. In a controller, this means using request.reader.text.

def index() {
    def body = request.reader.text
    respond body
}

In a test class the controller method is called multiple times as there are multiple tests.

def "test"() {
    when:
    controller.index()

    then:
    true
}

def "test2"() {
    when:
    controller.index()

    then:
    true
}

This is a problem when the body is empty. When executing the second test, it fails with java.io.IOException: Stream closed. The tests are not independent.

Please note that when the body is not empty, i.e.
request.json = [hello: "world"]
the tests pass.

Please also note that replacing request.reader.text with request.JSON in the controller causes the tests to pass. This is specifically for reading the body text.