Add rudimentary regexp-based run by line number (#3)

* Refactor to add a fixtures_path test helper

* Add rudimentary regexp-based run by line number

* Small regexp tweaks

lib/mighty_test.rb

@@ -3,4 +3,5 @@ module MightyTest
   autoload :CLI, "mighty_test/cli"
   autoload :MinitestRunner, "mighty_test/minitest_runner"
   autoload :OptionParser, "mighty_test/option_parser"
+  autoload :TestParser, "mighty_test/test_parser"
 end

lib/mighty_test/cli.rb

@@ -13,6 +13,8 @@ def run(argv: ARGV)
         print_help
       elsif options[:version]
         puts VERSION
+      elsif path_args.grep(/.:\d+$/).any?
+        run_test_by_line_number
       else
         run_tests_by_path
       end
@@ -31,6 +33,17 @@ def print_help
       runner.print_help_and_exit!
     end
 
+    def run_test_by_line_number
+      path, line = path_args.first.match(/^(.+):(\d+)$/).captures
+      test_name = TestParser.new(path).test_name_at_line(line.to_i)
+
+      if test_name
+        runner.run_inline_and_exit!(path, args: ["-n", "/^#{Regexp.quote(test_name)}$/"] + extra_args)
+      else
+        runner.run_inline_and_exit!(args: extra_args)
+      end
+    end
+
     def run_tests_by_path
       runner.run_inline_and_exit!(*path_args, args: extra_args)
     end

lib/mighty_test/test_parser.rb

@@ -0,0 +1,33 @@
+module MightyTest
+  class TestParser
+    def initialize(test_path)
+      @path = test_path.to_s
+    end
+
+    def test_name_at_line(number)
+      method_name = nil
+      lines = File.read(path).lines
+      lines[2...number].reverse_each.find do |line|
+        method_name =
+          match_minitest_method_name(line) ||
+          match_active_support_test_string(line)&.then { "test_#{_1.gsub(/\s+/, '_')}" }
+      end
+      method_name
+    end
+
+    private
+
+    attr_reader :path
+
+    def match_minitest_method_name(line)
+      line[/^\s*(?:focus\s+)?def\s+(test_\w+)/, 1]
+    end
+
+    def match_active_support_test_string(line)
+      match = line.match(/^\s*test\s+(?:"(.+?)"|'(.+?)')\s*do\s*(?:#.*?)?$/)
+      return unless match
+
+      match.captures.compact.first
+    end
+  end
+end

test/fixtures/active_support_test.rb

@@ -0,0 +1,11 @@
+require "rails_helper"
+
+class ActiveSupportTest < ActiveSupport::TestCase
+  test "it's important" do # Trailing comment OK
+    assert true # rubocop:disable Minitest/UselessAssertion
+  end
+
+  test 'it does something "interesting"' do
+    assert true # rubocop:disable Minitest/UselessAssertion
+  end
+end

test/fixtures/example_project/test/failing_test.rb

@@ -4,4 +4,8 @@ class FailingTest < Minitest::Test
   def test_assertion_fails
     assert_equal "foo", "bar"
   end
+
+  def test_assertion_succeeds
+    assert true # rubocop:disable Minitest/UselessAssertion
+  end
 end

test/integration/mt_test.rb

@@ -2,14 +2,16 @@
 
 module MightyTest
   class MtTest < Minitest::Test
+    include FixturesPath
+
     def test_mt_can_run_and_print_version
       result = bundle_exec_mt(argv: ["--version"])
 
       assert_equal(VERSION, result.stdout.chomp)
     end
 
     def test_mt_runs_a_successful_test
-      project_dir = File.expand_path("../fixtures/example_project", __dir__)
+      project_dir = fixtures_path.join("example_project")
       result = bundle_exec_mt(argv: ["test/example_test.rb"], chdir: project_dir)
 
       assert_match(/Run options:.* --seed \d+/, result.stdout)
@@ -18,27 +20,43 @@ def test_mt_runs_a_successful_test
     end
 
     def test_mt_runs_a_failing_test_and_exits_with_non_zero_status
-      project_dir = File.expand_path("../fixtures/example_project", __dir__)
+      project_dir = fixtures_path.join("example_project")
       result = bundle_exec_mt(argv: ["test/failing_test.rb"], chdir: project_dir, raise_on_failure: false)
 
       assert_predicate(result, :failure?)
       assert_match(/\d runs, \d assertions, 1 failures, 0 errors/, result.stdout)
     end
 
     def test_mt_supports_test_focus
-      project_dir = File.expand_path("../fixtures/example_project", __dir__)
+      project_dir = fixtures_path.join("example_project")
       result = bundle_exec_mt(argv: ["test/focused_test.rb"], chdir: project_dir)
 
-      assert_match(/1 runs, 1 assertions, 0 failures, 0 errors/, result.stdout)
+      assert_match(/\b1 runs, 1 assertions, 0 failures, 0 errors/, result.stdout)
     end
 
     def test_mt_passes_fail_fast_flag_to_minitest
-      project_dir = File.expand_path("../fixtures/example_project", __dir__)
+      project_dir = fixtures_path.join("example_project")
       result = bundle_exec_mt(argv: ["--fail-fast", "test/example_test.rb"], chdir: project_dir)
 
       assert_match(/Run options:.* --fail-fast/, result.stdout)
     end
 
+    def test_mt_runs_a_single_test_by_line_number_with_verbose_output
+      project_dir = fixtures_path.join("example_project")
+      result = bundle_exec_mt(argv: ["--verbose", "test/failing_test.rb:9"], chdir: project_dir)
+
+      assert_includes(result.stdout, "FailingTest#test_assertion_succeeds")
+      assert_match(/\b1 assertions/, result.stdout)
+    end
+
+    def test_mt_runs_no_tests_if_line_number_doesnt_match
+      project_dir = fixtures_path.join("example_project")
+      result = bundle_exec_mt(argv: ["--verbose", "test/failing_test.rb:2"], chdir: project_dir)
+
+      assert_match(/Run options:.* --verbose/, result.stdout)
+      refute_match(/FailingTest/, result.stdout)
+    end
+
     private
 
     def bundle_exec_mt(argv:, env: { "CI" => nil }, chdir: nil, raise_on_failure: true)

test/mighty_test/test_parser_test.rb

@@ -0,0 +1,38 @@
+require "test_helper"
+
+module MightyTest
+  class TestParserTest < Minitest::Test
+    include FixturesPath
+
+    def test_returns_nil_if_no_test_found
+      name = test_name_at_line(fixtures_path.join("example_project/test/example_test.rb"), 3)
+      assert_nil name
+    end
+
+    def test_finds_traditional_test_name_by_line_number
+      name = test_name_at_line(fixtures_path.join("example_project/test/example_test.rb"), 5)
+      assert_equal "test_that_it_has_a_version_number", name
+    end
+
+    def test_finds_traditional_test_name_by_line_number_even_with_focus
+      name = test_name_at_line(fixtures_path.join("example_project/test/focused_test.rb"), 5)
+      assert_equal "test_this_test_is_run", name
+    end
+
+    def test_finds_active_support_test_name_by_line_number
+      name = test_name_at_line(fixtures_path.join("active_support_test.rb"), 5)
+      assert_equal "test_it's_important", name
+    end
+
+    def test_finds_single_quoted_active_support_test_name_by_line_number
+      name = test_name_at_line(fixtures_path.join("active_support_test.rb"), 9)
+      assert_equal 'test_it_does_something_"interesting"', name
+    end
+
+    private
+
+    def test_name_at_line(path, line_number)
+      TestParser.new(path).test_name_at_line(line_number)
+    end
+  end
+end

test/support/fixtures_path.rb

@@ -0,0 +1,7 @@
+module FixturesPath
+  private
+
+  def fixtures_path
+    Pathname.new(File.expand_path("../fixtures", __dir__))
+  end
+end