Add fail_if_no_examples option: exit 1 if no RSpec examples

Default behavior not changed. CLI option not implemented.

Author: xmik

features/configuration/fail_if_no_examples.feature

@@ -0,0 +1,106 @@
+Feature: fail if no examples
+
+  Use the `fail_if_no_examples` option to make RSpec return non zero exit status
+   when there are 0 examples.
+
+  Scenario: A failing spec example and `fail_if_no_examples` set to true
+    Given a file named "spec/spec_helper.rb" with:
+      """ruby
+      RSpec.configure { |c| c.fail_if_no_examples = true }
+      """
+    Given a file named "spec/example_spec.rb" with:
+      """ruby
+      require 'spec_helper'
+
+      RSpec.describe "something" do
+        it "fails" do
+          fail
+        end
+      end
+      """
+    When I run `rspec spec/example_spec.rb`
+    Then the exit status should be 1
+
+  Scenario: A failing spec example and `fail_if_no_examples` set to false
+    Given a file named "spec/spec_helper.rb" with:
+      """ruby
+      RSpec.configure { |c| c.fail_if_no_examples = false }
+      """
+    Given a file named "spec/example_spec.rb" with:
+      """ruby
+      require 'spec_helper'
+
+      RSpec.describe "something" do
+        it "fails" do
+          fail
+        end
+      end
+      """
+    When I run `rspec spec/example_spec.rb`
+    Then the exit status should be 1
+
+  Scenario: A passing spec example and `fail_if_no_examples` set to true
+    Given a file named "spec/spec_helper.rb" with:
+      """ruby
+      RSpec.configure { |c| c.fail_if_no_examples = true }
+      """
+    Given a file named "spec/example_spec.rb" with:
+      """ruby
+      require 'spec_helper'
+
+      RSpec.describe "something" do
+        it "succeeds" do
+          true
+        end
+      end
+      """
+    When I run `rspec spec/example_spec.rb`
+    Then the exit status should be 0
+
+  Scenario: A passing spec example and `fail_if_no_examples` set to false
+    Given a file named "spec/spec_helper.rb" with:
+      """ruby
+      RSpec.configure { |c| c.fail_if_no_examples = false }
+      """
+    Given a file named "spec/example_spec.rb" with:
+      """ruby
+      require 'spec_helper'
+
+      RSpec.describe "something" do
+        it "succeeds" do
+          true
+        end
+      end
+      """
+    When I run `rspec spec/example_spec.rb`
+    Then the exit status should be 0
+
+  Scenario: No examples and `fail_if_no_examples` set to true
+    Given a file named "spec/spec_helper.rb" with:
+      """ruby
+      RSpec.configure { |c| c.fail_if_no_examples = true }
+      """
+    Given a file named "spec/example_spec.rb" with:
+      """ruby
+      require 'spec_helper'
+
+      RSpec.describe "something" do
+      end
+      """
+    When I run `rspec spec/example_spec.rb`
+    Then the exit status should be 1
+
+  Scenario: No examples and `fail_if_no_examples` set to false
+   Given a file named "spec/spec_helper.rb" with:
+     """ruby
+     RSpec.configure { |c| c.fail_if_no_examples = false }
+     """
+   Given a file named "spec/example_spec.rb" with:
+     """ruby
+     require 'spec_helper'
+
+     RSpec.describe "something" do
+     end
+     """
+   When I run `rspec spec/example_spec.rb`
+   Then the exit status should be 0

lib/rspec/core/configuration.rb

@@ -199,6 +199,10 @@ def only_failures_but_not_configured?
       # The exit code to return if there are any failures (default: 1).
       add_setting :failure_exit_code
 
+      # @macro add_setting
+      # Whether or not to fail when there are no RSpec examples (default: false).
+      add_setting :fail_if_no_examples
+
       # @macro define_reader
       # Indicates files configured to be required.
       define_reader :requires
@@ -425,6 +429,7 @@ def initialize
         @pattern = '**{,/*/**}/*_spec.rb'
         @exclude_pattern = ''
         @failure_exit_code = 1
+        @fail_if_no_examples = false
         @spec_files_loaded = false
 
         @backtrace_formatter = BacktraceFormatter.new

lib/rspec/core/runner.rb

@@ -110,6 +110,9 @@ def setup(err, out)
       def run_specs(example_groups)
         @configuration.reporter.report(@world.example_count(example_groups)) do |reporter|
           @configuration.with_suite_hooks do
+            if @world.example_count(example_groups) == 0 && @configuration.fail_if_no_examples
+              return 1
+            end
             example_groups.map { |g| g.run(reporter) }.all? ? 0 : @configuration.failure_exit_code
           end
         end

spec/rspec/core/configuration_spec.rb

@@ -42,6 +42,22 @@ module RSpec::Core
       end
     end
 
+    describe 'fail_if_no_examples' do
+      it 'defaults to false' do
+        expect(RSpec::Core::Configuration.new.fail_if_no_examples).to be(false)
+      end
+
+      it 'can be set to true' do
+        config.fail_if_no_examples = true
+        expect(config.fail_if_no_examples).to eq(true)
+      end
+
+      it 'can be set to false' do
+        config.fail_if_no_examples = false
+        expect(config.fail_if_no_examples).to eq(false)
+      end
+    end
+
     describe '#deprecation_stream' do
       it 'defaults to standard error' do
         expect($rspec_core_without_stderr_monkey_patch.deprecation_stream).to eq STDERR