make it possible to customize the executable inside rereun snippets.

In the Rails repository we use a `bin/test` executable to run our tests.
However the rerun snippets still included `bin/rails test`:

BEFORE:
```
Failed tests:

bin/rails test test/cases/adapters/postgresql/schema_test.rb:91
```

AFTER:
```
Failed tests:

bin/test test/cases/adapters/postgresql/schema_test.rb:91
```

railties/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Make it possible to customize the executable inside rerun snippets.
+
+    *Yves Senn*
+
 *   Add support for API only apps.
     Middleware stack was slimmed down and it has only the needed
     middleware for API apps & generators generates the right files,

railties/lib/rails/test_unit/reporter.rb

@@ -1,7 +1,11 @@
+require "active_support/core_ext/class/attribute"
 require "minitest"
 
 module Rails
   class TestUnitReporter < Minitest::StatisticsReporter
+    class_attribute :executable
+    self.executable = "bin/rails test"
+
     def report
       return if results.empty?
       io.puts
@@ -15,7 +19,7 @@ def aggregated_results # :nodoc:
       filtered_results.reject!(&:skipped?) unless options[:verbose]
       filtered_results.map do |result|
         location, line = result.method(result.name).source_location
-        "bin/rails test #{relative_path_for(location)}:#{line}"
+        "#{self.executable} #{relative_path_for(location)}:#{line}"
       end.join "\n"
     end
 

railties/test/test_unit/reporter_test.rb

@@ -43,6 +43,20 @@ def woot; end
     assert_rerun_snippet_count 1
   end
 
+  test "allows to customize the executable in the rerun snippet" do
+    original_executable = Rails::TestUnitReporter.executable
+    begin
+      Rails::TestUnitReporter.executable = "bin/test"
+      verbose = Rails::TestUnitReporter.new @output, verbose: true
+      @reporter.record(failed_test)
+      @reporter.report
+
+      assert_match %r{^bin/test .*test/test_unit/reporter_test.rb:6$}, @output.string
+    ensure
+      Rails::TestUnitReporter.executable = original_executable
+    end
+  end
+
   private
   def assert_rerun_snippet_count(snippet_count)
     assert_equal snippet_count, @output.string.scan(%r{^bin/rails test }).size

tools/test.rb

@@ -8,3 +8,5 @@ def self.root
     @root ||= Pathname.new(COMPONENT_ROOT)
   end
 end
+
+Rails::TestUnitReporter.executable = "bin/test"