[ruby/irb] Change show_source tests into integration tests

* Remove trailing spaces

* Migrate show_source tests to integration tests

Because show_source tests often need to define class and/or methods,
they can easily leak state to other tests. Changing them to integration
tests will ensure that they are run in a clean environment.

* Fix NoMethodError caused by SourceFinder#method_target

https://github.com/ruby/irb/commit/3c39f13397c72a8db24e50afdcb8942e6c4ea12f

2 files changed, 263 insertions, 228 deletions

diff --git a/test/irb/cmd/test_show_source.rb b/test/irb/cmd/test_show_source.rb
new file mode 100644
index 0000000000..89b1142390
--- /dev/null
+++ b/test/irb/cmd/test_show_source.rb
@@ -0,0 +1,263 @@
+# frozen_string_literal: false
+require 'irb'
+
+require_relative "../helper"
+
+module TestIRB
+  class ShowSourceTest < IntegrationTestCase
+    def setup
+      super
+
+      write_rc <<~'RUBY'
+        IRB.conf[:USE_PAGER] = false
+      RUBY
+    end
+
+    def test_show_source
+      write_ruby <<~'RUBY'
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source IRB.conf"
+        type "exit"
+      end
+
+      assert_match(%r[/irb\/init\.rb], out)
+    end
+
+    def test_show_source_alias
+      write_ruby <<~'RUBY'
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "$ IRB.conf"
+        type "exit"
+      end
+
+      assert_match(%r[/irb\/init\.rb], out)
+    end
+
+    def test_show_source_string
+      write_ruby <<~'RUBY'
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source 'IRB.conf'"
+        type "exit"
+      end
+
+      assert_match(%r[/irb\/init\.rb], out)
+    end
+
+    def test_show_source_method_s
+      write_ruby <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#foo -s"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+def foo\r\n  end\r\n], out)
+    end
+
+    def test_show_source_method_s_with_incorrect_signature
+      write_ruby <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#fooo -s"
+        type "exit"
+      end
+
+      assert_match(%r[Error: Couldn't locate a super definition for Bar#fooo], out)
+    end
+
+    def test_show_source_private_method
+      write_ruby <<~RUBY
+        class Bar
+          private def foo
+          end
+        end
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#foo"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+private def foo\r\n  end\r\n], out)
+    end
+
+    def test_show_source_private_singleton_method
+      write_ruby <<~RUBY
+        class Bar
+          private def foo
+          end
+        end
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "bar = Bar.new"
+        type "show_source bar.foo"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+private def foo\r\n  end\r\n], out)
+    end
+
+    def test_show_source_method_multiple_s
+      write_ruby <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        class Bob < Bar
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bob#foo -ss"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+def foo\r\n  end\r\n], out)
+    end
+
+    def test_show_source_method_no_instance_method
+      write_ruby <<~RUBY
+        class Baz
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#foo -s"
+        type "exit"
+      end
+
+      assert_match(%r[Error: Couldn't locate a super definition for Bar#foo], out)
+    end
+
+    def test_show_source_method_exceeds_super_chain
+      write_ruby <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#foo -ss"
+        type "exit"
+      end
+
+      assert_match(%r[Error: Couldn't locate a super definition for Bar#foo], out)
+    end
+
+    def test_show_source_method_accidental_characters
+      write_ruby <<~'RUBY'
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "show_source Bar#foo -sddddd"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+def foo\r\n  end], out)
+    end
+
+    def test_show_source_receiver_super
+      write_ruby <<~RUBY
+        class Baz
+          def foo
+          end
+        end
+
+        class Bar < Baz
+          def foo
+            super
+          end
+        end
+
+        binding.irb
+      RUBY
+
+      out = run_ruby_file do
+        type "bar = Bar.new"
+        type "show_source bar.foo -s"
+        type "exit"
+      end
+
+      assert_match(%r[#{@ruby_file.to_path}:2\s+def foo\r\n  end], out)
+    end
+  end
+end
diff --git a/test/irb/test_cmd.rb b/test/irb/test_cmd.rb
index ee987920f3..345f04bcf2 100644
--- a/test/irb/test_cmd.rb
+++ b/test/irb/test_cmd.rb
@@ -449,234 +449,6 @@ module TestIRB
     end
   end
 
-  class ShowSourceTest < CommandTestCase
-    def test_show_source
-      out, err = execute_lines(
-        "show_source IRB.conf\n",
-      )
-      assert_empty err
-      assert_match(%r[/irb\/init\.rb], out)
-    end
-
-    def test_show_source_method
-      out, err = execute_lines(
-        "p show_source('IRB.conf')\n",
-      )
-      assert_empty err
-      assert_match(%r[/irb\/init\.rb], out)
-    end
-
-    def test_show_source_method_s
-      code = <<~RUBY
-        class Baz
-          def foo
-          end
-        end
-      
-        class Bar < Baz
-          def foo
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbar.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbar.rb'\n",
-        "show_source Bar#foo -s",
-      )
-      assert_match(%r[bazbar.rb:2\n\n  def foo\n  end\n\n=> nil\n], out)
-      File.delete("#{@tmpdir}/bazbar.rb")
-    end
-
-    def test_show_source_method_multiple_s
-      code = <<~RUBY
-        class Baz
-          def fob
-          end
-        end
-      
-        class Bar < Baz
-          def fob
-            super
-          end
-        end
-
-        class Bob < Bar
-          def fob
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbarbob.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbarbob.rb'\n",
-        "show_source Bob#fob -ss",
-      )
-      assert_match(%r[bazbarbob.rb:2\n\n  def fob\n  end\n\n=> nil\n], out)
-      File.delete("#{@tmpdir}/bazbarbob.rb")
-    end
-
-    def test_show_source_method_no_instance_method
-      code = <<~RUBY
-        class Baz
-        end
-      
-        class Bar < Baz
-          def fee
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbar.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbar.rb'\n",
-        "show_source Bar#fee -s",
-      )
-      assert_match(%r[Error: Couldn't locate a super definition for Bar#fee\n], out)
-      File.delete("#{@tmpdir}/bazbar.rb")
-    end
-
-    def test_show_source_method_exceeds_super_chain
-      code = <<~RUBY
-        class Baz
-          def fow
-          end
-        end
-      
-        class Bar < Baz
-          def fow
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbar.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbar.rb'\n",
-        "show_source Bar#fow -ss",
-      )
-      assert_match(%r[Error: Couldn't locate a super definition for Bar#fow\n], out)
-      File.delete("#{@tmpdir}/bazbar.rb")
-    end
-
-    def test_show_source_method_accidental_characters
-      code = <<~RUBY
-        class Baz
-          def fol
-          end
-        end
-      
-        class Bar < Baz
-          def fol
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbar.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbar.rb'\n",
-        "show_source Bar#fol -sddddd",
-      )
-
-      assert_match(%r[bazbar.rb:2\n\n  def fol\n  end\n\n=> nil\n], out)
-      File.delete("#{@tmpdir}/bazbar.rb")
-    end
-
-    def test_show_source_receiver_super
-      code = <<~RUBY
-        class Baz
-          def fot
-          end
-        end
-      
-        class Bar < Baz
-          def fot
-            super
-          end
-        end
-      RUBY
-      File.write("#{@tmpdir}/bazbar.rb", code)
-      out, err = execute_lines(
-        "irb_load '#{@tmpdir}/bazbar.rb'\n",
-        "bar = Bar.new",
-        "show_source bar.fot -s"
-      )
-      assert_match(%r[bazbar.rb:2\n\n  def fot\n  end\n\n=> nil\n], out)
-      File.delete("#{@tmpdir}/bazbar.rb")
-    end
-
-    def test_show_source_string
-      out, err = execute_lines(
-        "show_source 'IRB.conf'\n",
-      )
-      assert_empty err
-      assert_match(%r[/irb\/init\.rb], out)
-    end
-
-    def test_show_source_alias
-      out, err = execute_lines(
-        "$ 'IRB.conf'\n",
-        conf: { COMMAND_ALIASES: { :'$' => :show_source } }
-      )
-      assert_empty err
-      assert_match(%r[/irb\/init\.rb], out)
-    end
-
-    def test_show_source_end_finder
-      eval(code = <<-EOS, binding, __FILE__, __LINE__ + 1)
-        def show_source_test_method
-          unless true
-          end
-        end unless defined?(show_source_test_method)
-      EOS
-
-      out, err = execute_lines(
-        "show_source '#{self.class.name}#show_source_test_method'\n",
-      )
-
-      assert_empty err
-      assert_include(out, code)
-    end
-
-    def test_show_source_private_instance
-      eval(code = <<-EOS, binding, __FILE__, __LINE__ + 1)
-        class PrivateInstanceTest
-          private def show_source_test_method
-            unless true
-            end
-          end unless private_method_defined?(:show_source_test_method)
-        end
-      EOS
-
-      out, err = execute_lines(
-        "show_source '#{self.class.name}::PrivateInstanceTest#show_source_test_method'\n",
-      )
-
-      assert_empty err
-      assert_include(out, code.lines[1..-2].join)
-    end
-
-
-    def test_show_source_private
-      eval(code = <<-EOS, binding, __FILE__, __LINE__ + 1)
-        class PrivateTest
-          private def show_source_test_method
-            unless true
-            end
-          end unless private_method_defined?(:show_source_test_method)
-        end
-
-        Instance = PrivateTest.new unless defined?(Instance)
-      EOS
-
-      out, err = execute_lines(
-        "show_source '#{self.class.name}::Instance.show_source_test_method'\n",
-      )
-
-      assert_empty err
-      assert_include(out, code.lines[1..-4].join)
-    end
-  end
-
   class WorkspaceCommandTestCase < CommandTestCase
     def setup
       super