From 24005149003ad3e5179ae41ec791880953c10514 Mon Sep 17 00:00:00 2001
From: fatkodima <fatkodima123@gmail.com>
Date: Tue, 17 Jan 2023 16:56:25 +0200
Subject: [PATCH] Change what is considered a test case by `rubocop-minitest`

---
 .../change_what_is_considered_a_test_case.md  |  1 +
 .../cop/mixin/minitest_exploration_helpers.rb |  9 +++-
 lib/rubocop/minitest/assert_offense.rb        |  1 +
 .../minitest_exploration_helpers_test.rb      | 50 +++++++++++++++++++
 4 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 changelog/change_what_is_considered_a_test_case.md
 create mode 100644 test/rubocop/cop/mixin/minitest_exploration_helpers_test.rb

diff --git a/changelog/change_what_is_considered_a_test_case.md b/changelog/change_what_is_considered_a_test_case.md
new file mode 100644
index 00000000..120c40e5
--- /dev/null
+++ b/changelog/change_what_is_considered_a_test_case.md
@@ -0,0 +1 @@
+* [#231](https://github.com/rubocop/rubocop-minitest/pull/231): Change what is considered a test case by `rubocop-minitest` (`public` method without arguments with `test_` name prefix). ([@fatkodima][])
diff --git a/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb b/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
index 323524ac..d0a16054 100644
--- a/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
+++ b/lib/rubocop/cop/mixin/minitest_exploration_helpers.rb
@@ -7,6 +7,7 @@ module Cop
     # Helper methods for different explorations against test files and test cases.
     # @api private
     module MinitestExplorationHelpers
+      include DefNode
       extend NodePattern::Macros
 
       ASSERTION_PREFIXES = %w[assert refute].freeze
@@ -27,14 +28,14 @@ def test_class?(class_node)
       end
 
       def test_case?(node)
-        return false unless node&.def_type? && test_case_name?(node.method_name)
+        return false unless node&.def_type? && test_method?(node)
 
         class_ancestor = node.each_ancestor(:class).first
         test_class?(class_ancestor)
       end
 
       def test_cases(class_node)
-        test_cases = class_def_nodes(class_node).select { |def_node| test_case_name?(def_node.method_name) }
+        test_cases = class_def_nodes(class_node).select { |def_node| test_method?(def_node) }
 
         # Support Active Support's `test 'example' { ... }` method.
         # https://api.rubyonrails.org/classes/ActiveSupport/Testing/Declarative.html
@@ -43,6 +44,10 @@ def test_cases(class_node)
         test_cases + test_blocks
       end
 
+      def test_method?(def_node)
+        test_case_name?(def_node.method_name) && !def_node.arguments? && !non_public?(def_node)
+      end
+
       def lifecycle_hooks(class_node)
         class_def_nodes(class_node)
           .select { |def_node| lifecycle_hook_method?(def_node) }
diff --git a/lib/rubocop/minitest/assert_offense.rb b/lib/rubocop/minitest/assert_offense.rb
index be818dcf..e6ed160f 100644
--- a/lib/rubocop/minitest/assert_offense.rb
+++ b/lib/rubocop/minitest/assert_offense.rb
@@ -77,6 +77,7 @@ module AssertOffense
 
       def setup
         cop_name = self.class.to_s.delete_suffix('Test')
+        return unless RuboCop::Cop::Minitest.const_defined?(cop_name)
 
         @cop = RuboCop::Cop::Minitest.const_get(cop_name).new
       end
diff --git a/test/rubocop/cop/mixin/minitest_exploration_helpers_test.rb b/test/rubocop/cop/mixin/minitest_exploration_helpers_test.rb
new file mode 100644
index 00000000..b37b0ddf
--- /dev/null
+++ b/test/rubocop/cop/mixin/minitest_exploration_helpers_test.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class MinitestExplorationHelpersTest < Minitest::Test
+  module Helper
+    extend RuboCop::Cop::MinitestExplorationHelpers
+    class << self
+      public :test_case?
+    end
+  end
+
+  SOURCE = <<~RUBY
+    class FooTest < Minitest::Test
+      def not_test_case; end
+      def test_with_arguments(arg); end
+      def test_public; end
+
+      protected
+      def test_protected; end
+
+      private
+      def test_private; end
+    end
+  RUBY
+
+  def test_test_case_returns_true_for_test_case
+    assert Helper.test_case?(method_node(:test_public))
+  end
+
+  def test_test_case_returns_false_for_hidden_test_methods
+    refute Helper.test_case?(method_node(:test_protected))
+    refute Helper.test_case?(method_node(:test_private))
+  end
+
+  def test_test_case_returns_false_for_non_test_methods
+    refute Helper.test_case?(method_node(:non_test_case))
+  end
+
+  def test_test_case_returns_false_for_test_methods_with_arguments
+    refute Helper.test_case?(method_node(:test_with_arguments))
+  end
+
+  private
+
+  def method_node(method_name)
+    class_node = parse_source!(SOURCE).ast
+    class_node.body.each_child_node(:def).find { |def_node| def_node.method?(method_name) }
+  end
+end