Merge pull request #1879 from rspec/better-avoid-generated-descriptions-tests

Beef up tests for when rspec-expectations is not available.

Author: JonRowe

features/expectation_framework_integration/configure_expectation_framework.feature

@@ -45,7 +45,8 @@ Feature: configure expectation framework
     Then the examples should all pass
 
   Scenario: Configure test/unit assertions
-    Given a file named "example_spec.rb" with:
+    Given rspec-expectations is not installed
+      And a file named "example_spec.rb" with:
       """ruby
       RSpec.configure do |config|
         config.expect_with :test_unit
@@ -72,7 +73,8 @@ Feature: configure expectation framework
     And  the output should contain "3 examples, 1 failure"
 
   Scenario: Configure minitest assertions
-    Given a file named "example_spec.rb" with:
+    Given rspec-expectations is not installed
+      And a file named "example_spec.rb" with:
       """ruby
       RSpec.configure do |config|
         config.expect_with :minitest
@@ -146,7 +148,8 @@ Feature: configure expectation framework
     Then the examples should all pass
 
   Scenario: Configure test/unit and minitest assertions
-    Given a file named "example_spec.rb" with:
+    Given rspec-expectations is not installed
+      And a file named "example_spec.rb" with:
       """ruby
       RSpec.configure do |config|
         config.expect_with :test_unit, :minitest

features/step_definitions/core_standalone_steps.rb

@@ -10,3 +10,7 @@
   # rspec-expectations from the load path.
   set_env('REMOVE_OTHER_RSPEC_LIBS_FROM_LOAD_PATH', 'true')
 end
+
+Given(/^rspec-expectations is not installed$/) do
+  step "only rspec-core is installed"
+end

spec/rspec/core/example_spec.rb

@@ -187,12 +187,28 @@ def assert(val)
     end
 
     context "when `expect_with :stdlib` is configured" do
-      before(:each) { expect_with :stdlib }
+      around do |ex|
+        # Prevent RSpec::Matchers from being autoloaded.
+        orig_autoloads = RSpec::MODULES_TO_AUTOLOAD.dup
+        RSpec::MODULES_TO_AUTOLOAD.clear
+        ex.run
+        RSpec::MODULES_TO_AUTOLOAD.replace(orig_autoloads)
+      end
+
+      before { expect_with :stdlib }
 
-      it "does not attempt to get the generated description from RSpec::Matchers" do
-        expect(RSpec::Matchers).not_to receive(:generated_description)
-        example_group.example { assert 5 == 5 }
+      it "does not attempt to get the generated description from RSpec::Matchers when not loaded" do
+        # Hide the constant while the example runs to simulate it being unloaded.
+        example_group.before { hide_const("RSpec::Matchers") }
+
+        ex = example_group.example { assert 5 == 5 }
         example_group.run
+
+        # We rescue errors that occur while generating the description and append it,
+        # so this ensures that no error mentioning `RSpec::Matchers` occurred while
+        # generating the description.
+        expect(ex.description).not_to include("RSpec::Matchers")
+        expect(ex).to pass
       end
 
       it "uses the file and line number" do