Add test_pid tag to ExUnit.Case

Closes #13880.

Author: josevalim

lib/ex_unit/lib/ex_unit/case.ex

@@ -147,30 +147,32 @@ defmodule ExUnit.Case do
   The following tags are set automatically by ExUnit and are
   therefore reserved:
 
-    * `:module` - the module on which the test was defined
+    * `:async` - if the test case is in async mode
 
     * `:file` - the file on which the test was defined
 
     * `:line` - the line on which the test was defined
 
+    * `:module` - the module on which the test was defined
+
+    * `:registered` - used for `ExUnit.Case.register_attribute/3` values
+
     * `:test` - the test name
 
-    * `:async` - if the test case is in async mode
+    * `:test_pid` - the PID of the testing process
 
-    * `:registered` - used for `ExUnit.Case.register_attribute/3` values
+    * `:test_type` - the test type used when printing test results.
+      It is set by ExUnit to `:test`, `:doctest` and so on, but is customizable.
 
-    * `:describe` - the describe block the test belongs to
+    * `:describe` - the describe block the test belongs to (if in a describe)
 
-    * `:describe_line` - the line the describe block begins on
+    * `:describe_line` - the line the describe block begins on (if in a describe)
 
     * `:doctest` - the module or the file being doctested (if a doctest)
 
-    * `:doctest_line` - the line the doctest was defined (if a doctest)
-
     * `:doctest_data` - additional metadata about doctests (if a doctest)
 
-    * `:test_type` - the test type used when printing test results.
-      It is set by ExUnit to `:test`, `:doctest` and so on, but is customizable.
+    * `:doctest_line` - the line the doctest was defined (if a doctest)
 
   The following tags customize how tests behave:
 

lib/ex_unit/lib/ex_unit/runner.ex

@@ -426,7 +426,7 @@ defmodule ExUnit.Runner do
     spawn_monitor(fn ->
       ExUnit.OnExitHandler.register(self())
       generate_test_seed(seed, test, rand_algorithm)
-      context = Map.merge(context, test.tags)
+      context = context |> Map.merge(test.tags) |> Map.put(:test_pid, self())
       capture_log = Map.get(context, :capture_log, capture_log)
 
       {time, test} =

lib/ex_unit/test/ex_unit/case_test.exs

@@ -28,10 +28,12 @@ defmodule ExUnit.CaseTest do
   @tag world: :good
   test "tags", context do
     line = __ENV__.line - 1
+    assert context[:async] == true
+    assert context[:line] == line
     assert context[:module] == __MODULE__
     assert context[:test] == __ENV__.function |> elem(0)
-    assert context[:line] == line
-    assert context[:async] == true
+    assert context[:test_pid] == self()
+    assert context[:test_type] == :test
     assert context[:hello] == true
     assert context[:world] == :good
   end