Adds a rails test:all rake task (#39221)

* Adds a rails test:all rake task

This task runs all tests, including system tests.

* Better placement + slight tweak of the comment

Co-authored-by: David Heinemeier Hansson <david@loudthinking.com>

guides/source/testing.md

@@ -857,6 +857,7 @@ bin/rails test:system
 
 NOTE: By default, running `bin/rails test` won't run your system tests.
 Make sure to run `bin/rails test:system` to actually run them.
+You can also run `bin/rails test:all` to run all tests, including system tests.
 
 #### Creating Articles System Test
 

railties/CHANGELOG.md

@@ -1,3 +1,9 @@
+*   Adds `rails test:all` for running all tests in the test directory.
+
+    This runs all test files in the test directory, including system tests.
+
+    *Niklas Häusele*
+
 *   Add `config.generators.after_generate` for processing to generated files.
 
     Register a callback that will get called right after generators has finished.

railties/lib/rails/test_unit/testing.rake

@@ -35,6 +35,12 @@ namespace :test do
     end
   end
 
+  desc "Runs all tests, including system tests"
+  task all: "test:prepare" do
+    $: << "test"
+    Rails::TestUnit::Runner.rake_run(["test/**/*_test.rb"])
+  end
+
   task generators: "test:prepare" do
     $: << "test"
     Rails::TestUnit::Runner.rake_run(["test/lib/generators"])