tests: add exceptions for tests that use curl to download local files

These are acceptable ways to use curl in local, non-network tests.

Library/Homebrew/test/cask/cask_spec.rb

@@ -46,13 +46,15 @@
  expect(c.token).to eq("caffeine")
  end
 
- it "returns an instance of the Cask from a URL" do
+ it "returns an instance of the Cask from a URL", :allow_utils_curl do
+ expect(Homebrew::API).not_to receive(:fetch_json_api_file)
  c = Cask::CaskLoader.load("file://#{tap_path}/Casks/local-caffeine.rb")
  expect(c).to be_a(described_class)
  expect(c.token).to eq("local-caffeine")
  end
 
- it "raises an error when failing to download a Cask from a URL" do
+ it "raises an error when failing to download a Cask from a URL", :allow_utils_curl do
+ expect(Homebrew::API).not_to receive(:fetch_json_api_file)
  expect do
  Cask::CaskLoader.load("file://#{tap_path}/Casks/notacask.rb")
  end.to raise_error(Cask::CaskUnavailableError)

Library/Homebrew/test/formulary_spec.rb

@@ -119,7 +119,8 @@ class Wrong#{described_class.class_s(formula_name)} < Formula
  expect(described_class.factory(formula_path)).to be_a(Formula)
  end
 
- it "returns a Formula when given a URL" do
+ it "returns a Formula when given a URL", :allow_utils_curl do
+ expect(Homebrew::API).not_to receive(:fetch_json_api_file)
  formula = described_class.factory("file://#{formula_path}")
  expect(formula).to be_a(Formula)
  end

Library/Homebrew/test/spec_helper.rb

@@ -173,6 +173,7 @@
 
  config.before do |example|
  next if example.metadata.key?(:needs_network)
+ next if example.metadata.key?(:allow_utils_curl)
 
  DISALLOWED_UTILS_CURL_METHODS.each do |method|
  allow(Utils::Curl).to receive(method).and_raise(<<~ERROR)