spec_helper: add :no_api test scope

This sets the HOMEBREW_NO_INSTALL_FROM_API environment variable
to prevent the selected tests from using the API. We will need
this as we transition to having the API be enabled by default
when running the tests but it's also nice as a sanity check
with the :needs_utils_curl scope in a few places.

Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb

@@ -22,11 +22,7 @@ RSpec.describe Cask::CaskLoader::FromAPILoader, :cask do
   describe ".can_load?" do
     include_context "with API setup", "test-opera"
 
-    context "when not using the API" do
-      before do
-        ENV["HOMEBREW_NO_INSTALL_FROM_API"] = "1"
-      end
-
+    context "when not using the API", :no_api do
       it "returns false" do
         expect(described_class.try_new(token)).to be_nil
       end

Library/Homebrew/test/cask/cask_loader_spec.rb

@@ -30,11 +30,7 @@ RSpec.describe Cask::CaskLoader, :cask do
           .and_return(cask_renames)
       end
 
-      context "when not using the API" do
-        before do
-          ENV["HOMEBREW_NO_INSTALL_FROM_API"] = "1"
-        end
-
+      context "when not using the API", :no_api do
         it "warns when using the short token" do
           expect do
             expect(described_class.for("version-newest")).to be_a Cask::CaskLoader::FromPathLoader
@@ -67,11 +63,7 @@ RSpec.describe Cask::CaskLoader, :cask do
       end
     end
 
-    context "when not using the API" do
-      before do
-        ENV["HOMEBREW_NO_INSTALL_FROM_API"] = "1"
-      end
-
+    context "when not using the API", :no_api do
       context "when a cask is migrated" do
         let(:token) { "local-caffeine" }
 

Library/Homebrew/test/cask/cask_spec.rb

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

Library/Homebrew/test/formulary_spec.rb

@@ -119,8 +119,7 @@ RSpec.describe Formulary do
       expect(described_class.factory(formula_path)).to be_a(Formula)
     end
 
-    it "returns a Formula when given a URL", :needs_utils_curl do
-      expect(Homebrew::API).not_to receive(:fetch_json_api_file)
+    it "returns a Formula when given a URL", :needs_utils_curl, :no_api do
       formula = described_class.factory("file://#{formula_path}")
       expect(formula).to be_a(Formula)
     end

Library/Homebrew/test/spec_helper.rb

@@ -174,6 +174,10 @@ RSpec.configure do |config|
     ERROR
   end
 
+  config.before(:each, :no_api) do
+    ENV["HOMEBREW_NO_INSTALL_FROM_API"] = "1"
+  end
+
   config.before(:each, :needs_svn) do
     svn_shim = HOMEBREW_SHIMS_PATH/"shared/svn"
     skip "Subversion is not installed." unless quiet_system svn_shim, "--version"

Library/Homebrew/test/tap_spec.rb

@@ -488,8 +488,7 @@ RSpec.describe Tap do
         expect(described_class.to_a).to include(CoreTap.instance)
       end
 
-      it "omits the core tap without the api" do
-        ENV["HOMEBREW_NO_INSTALL_FROM_API"] = "1"
+      it "omits the core tap without the api", :no_api do
         expect(described_class.to_a).not_to include(CoreTap.instance)
       end
     end