Add feature tests for JSON formatter

features/config_json_formatter.feature

@@ -0,0 +1,43 @@
+@test_unit @config
+Feature:
+
+  SimpleCov::Formatter::JSONFormatter is one of the
+  formatters included by default, useful for exporting
+  coverage results in JSON format.
+
+  Background:
+    Given I'm working on the project "faked_project"
+  Scenario: With JSONFormatter
+    Given SimpleCov for Test/Unit is configured with:
+      """
+      require 'simplecov'
+      require 'simplecov_json_formatter'
+      SimpleCov.formatter = SimpleCov::Formatter::JSONFormatter
+      SimpleCov.at_exit do
+        puts SimpleCov.result.format!
+      end
+      SimpleCov.start do
+        add_group 'Libs', 'lib/faked_project/'
+      end
+      """
+
+    When I successfully run `bundle exec rake test`
+    Then a JSON coverage report should have been generated in "coverage"
+    And the output should contain "JSON Coverage report generated"
+
+  Scenario: When CC_TEST_REPORTER_ID is set in the environment
+    Given SimpleCov for Test/Unit is configured with:
+      """
+      ENV['CC_TEST_REPORTER_ID'] = "9719ac886877886b7e325d1e828373114f633683e429107d1221d25270baeabf"
+      require 'simplecov'
+      SimpleCov.at_exit do
+        puts SimpleCov.result.format!
+      end
+      SimpleCov.start do
+        add_group 'Libs', 'lib/faked_project/'
+      end
+      """
+
+    When I successfully run `bundle exec rake test`
+    Then a JSON coverage report should have been generated in "coverage"
+    And the output should contain "JSON Coverage report generated"

features/step_definitions/json_steps.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+Then /^the JSON coverage report should map:/ do |expected_report|
+  cd(".") do
+    json_report = File.open("coverage/coverage.json").read
+    expected_report = ERB.new(expected_report).result(binding)
+    expect(json_report).to eq(expected_report)
+  end
+end

features/step_definitions/simplecov_steps.rb

@@ -46,6 +46,16 @@
     )
 end
 
+Then /^a JSON coverage report should have been generated(?: in "([^"]*)")?$/ do |coverage_dir|
+  coverage_dir ||= "coverage"
+  steps %(
+    Then the output should contain "Coverage report generated"
+    And a directory named "#{coverage_dir}" should exist
+    And the following files should exist:
+      | #{coverage_dir}/coverage.json      |
+    )
+end
+
 Then /^no coverage report should have been generated(?: in "([^"]*)")?$/ do |coverage_dir|
   coverage_dir ||= "coverage"
   steps %(

features/test_unit_basic.feature

@@ -35,3 +35,190 @@ Feature:
 
     And the report should be based upon:
       | Unit Tests |
+
+  Scenario:
+    Given SimpleCov for Test/Unit is configured with:
+      """
+      ENV['CC_TEST_REPORTER_ID'] = "9719ac886877886b7e325d1e828373114f633683e429107d1221d25270baeabf"
+      require 'simplecov'
+      SimpleCov.start
+      """
+
+    When I open the coverage report generated with `bundle exec rake test`
+    Then I should see the groups:
+      | name      | coverage | files |
+      | All Files | 91.38%   | 6     |
+
+    And I should see the source files:
+      | name                                    | coverage |
+      | lib/faked_project.rb                    | 100.00 %  |
+      | lib/faked_project/some_class.rb         | 80.00 %   |
+      | lib/faked_project/framework_specific.rb | 75.00 %   |
+      | lib/faked_project/meta_magic.rb         | 100.00 %  |
+      | test/meta_magic_test.rb                 | 100.00 %  |
+      | test/some_class_test.rb                 | 100.00 %  |
+
+      # Note: faked_test.rb is not appearing here since that's the first unit test file
+      # loaded by Rake, and only there test_helper is required, which then loads simplecov
+      # and triggers tracking of all other loaded files! Solution for this would be to
+      # configure simplecov in this first test instead of test_helper.
+
+    And the report should be based upon:
+      | Unit Tests |
+
+    And a JSON coverage report should have been generated
+    And the JSON coverage report should map:
+      """
+      {
+        "meta": {
+          "simplecov_version": "<%= SimpleCov::VERSION %>"
+        },
+        "coverage": {
+          "<%= Dir.pwd %>/lib/faked_project.rb": {
+            "lines": [
+              null,
+              null,
+              1,
+              1,
+              1,
+              null,
+              null,
+              null,
+              5,
+              3,
+              null,
+              null,
+              1
+            ]
+          },
+          "<%= Dir.pwd %>/lib/faked_project/framework_specific.rb": {
+            "lines": [
+              null,
+              null,
+              null,
+              null,
+              null,
+              1,
+              1,
+              1,
+              0,
+              null,
+              null,
+              1,
+              0,
+              null,
+              null,
+              1,
+              1,
+              null,
+              null,
+              null
+            ]
+          },
+          "<%= Dir.pwd %>/lib/faked_project/meta_magic.rb": {
+            "lines": [
+              null,
+              null,
+              1,
+              1,
+              1,
+              1,
+              null,
+              null,
+              null,
+              1,
+              1,
+              1,
+              null,
+              null,
+              null,
+              1,
+              1,
+              1,
+              null,
+              1,
+              1,
+              1,
+              null,
+              null,
+              null,
+              null
+            ]
+          },
+          "<%= Dir.pwd %>/lib/faked_project/some_class.rb": {
+            "lines": [
+              null,
+              null,
+              1,
+              1,
+              1,
+              null,
+              1,
+              2,
+              null,
+              null,
+              1,
+              1,
+              null,
+              null,
+              1,
+              1,
+              1,
+              null,
+              0,
+              null,
+              null,
+              0,
+              null,
+              null,
+              1,
+              null,
+              1,
+              0,
+              null,
+              null
+            ]
+          },
+          "<%= Dir.pwd %>/test/meta_magic_test.rb": {
+            "lines": [
+              null,
+              null,
+              1,
+              null,
+              1,
+              1,
+              1,
+              null,
+              null,
+              1,
+              1,
+              1,
+              1,
+              null,
+              null
+            ]
+          },
+          "<%= Dir.pwd %>/test/some_class_test.rb": {
+            "lines": [
+              null,
+              null,
+              1,
+              null,
+              1,
+              1,
+              2,
+              null,
+              null,
+              1,
+              1,
+              null,
+              null,
+              1,
+              1,
+              null,
+              null
+            ]
+          }
+        }
+      }
+      """