3 files changed, 193 insertions, 3 deletions
diff --git a/actionmailer/lib/action_mailer/test_case.rb b/actionmailer/lib/action_mailer/test_case.rb
index 108969ed4c..e60dda9694 100644
--- a/actionmailer/lib/action_mailer/test_case.rb
+++ b/actionmailer/lib/action_mailer/test_case.rb
@@ -10,6 +10,13 @@ module ActionMailer
   end
 
   class TestCase < ActiveSupport::TestCase
+
+    # Use AM::TestCase for the base class when describing a mailer
+    register_spec_type(self) do |desc|
+      Class === desc && desc < ActionMailer::Base
+    end
+    register_spec_type(/Mailer( ?Test)?\z/i, self)
+
     module Behavior
       extend ActiveSupport::Concern
 
@@ -42,9 +49,11 @@ module ActionMailer
         end
 
         def determine_default_mailer(name)
-          name.sub(/Test$/, '').constantize
-        rescue NameError
-          raise NonInferrableMailerError.new(name)
+          mailer = determine_constant_from_test_name(name) do |constant|
+            Class === constant && constant < ActionMailer::Base
+          end
+          raise NonInferrableMailerError.new(name) if mailer.nil?
+          mailer
         end
       end
 
diff --git a/actionmailer/test/spec_type_test.rb b/actionmailer/test/spec_type_test.rb
new file mode 100644
index 0000000000..90db59c2d2
--- /dev/null
+++ b/actionmailer/test/spec_type_test.rb
@@ -0,0 +1,37 @@
+require 'abstract_unit'
+
+class NotificationMailer < ActionMailer::Base; end
+class Notifications < ActionMailer::Base; end
+
+class SpecTypeTest < ActiveSupport::TestCase
+  def assert_mailer actual
+    assert_equal ActionMailer::TestCase, actual
+  end
+
+  def refute_mailer actual
+    refute_equal ActionMailer::TestCase, actual
+  end
+
+  def test_spec_type_resolves_for_class_constants
+    assert_mailer MiniTest::Spec.spec_type(NotificationMailer)
+    assert_mailer MiniTest::Spec.spec_type(Notifications)
+  end
+
+  def test_spec_type_resolves_for_matching_strings
+    assert_mailer MiniTest::Spec.spec_type("WidgetMailer")
+    assert_mailer MiniTest::Spec.spec_type("WidgetMailerTest")
+    assert_mailer MiniTest::Spec.spec_type("Widget Mailer Test")
+    # And is not case sensitive
+    assert_mailer MiniTest::Spec.spec_type("widgetmailer")
+    assert_mailer MiniTest::Spec.spec_type("widgetmailertest")
+    assert_mailer MiniTest::Spec.spec_type("widget mailer test")
+  end
+
+  def test_spec_type_wont_match_non_space_characters
+    refute_mailer MiniTest::Spec.spec_type("Widget Mailer\tTest")
+    refute_mailer MiniTest::Spec.spec_type("Widget Mailer\rTest")
+    refute_mailer MiniTest::Spec.spec_type("Widget Mailer\nTest")
+    refute_mailer MiniTest::Spec.spec_type("Widget Mailer\fTest")
+    refute_mailer MiniTest::Spec.spec_type("Widget MailerXTest")
+  end
+end
diff --git a/actionmailer/test/test_test.rb b/actionmailer/test/test_test.rb
index 86fd37bea6..139eb53359 100644
--- a/actionmailer/test/test_test.rb
+++ b/actionmailer/test/test_test.rb
@@ -26,3 +26,147 @@ class CrazyStringNameMailerTest < ActionMailer::TestCase
     assert_equal TestTestMailer, self.class.mailer_class
   end
 end
+
+describe TestTestMailer do
+  it "gets the mailer from the test name" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe TestTestMailer, :action do
+  it "gets the mailer from the test name" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe TestTestMailer do
+  describe "nested" do
+    it "gets the mailer from the test name" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe TestTestMailer, :action do
+  describe "nested" do
+    it "gets the mailer from the test name" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "TestTestMailer" do
+  it "gets the mailer from the test name" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "TestTestMailerTest" do
+  it "gets the mailer from the test name" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "TestTestMailer" do
+  describe "nested" do
+    it "gets the mailer from the test name" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "TestTestMailerTest" do
+  describe "nested" do
+    it "gets the mailer from the test name" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "AnotherCrazySymbolNameMailerTest" do
+  tests :test_test_mailer
+
+  it "gets the mailer after setting it with a symbol" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "AnotherCrazyStringNameMailerTest" do
+  tests 'test_test_mailer'
+
+  it "gets the mailer after setting it with a string" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "Another Crazy Name Mailer Test" do
+  tests TestTestMailer
+
+  it "gets the mailer after setting it manually" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "Another Crazy Symbol Name Mailer Test" do
+  tests :test_test_mailer
+
+  it "gets the mailer after setting it with a symbol" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "Another Crazy String Name Mailer Test" do
+  tests 'test_test_mailer'
+
+  it "gets the mailer after setting it with a string" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end
+
+describe "AnotherCrazySymbolNameMailerTest" do
+  tests :test_test_mailer
+
+  describe "nested" do
+    it "gets the mailer after setting it with a symbol" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "AnotherCrazyStringNameMailerTest" do
+  tests 'test_test_mailer'
+
+  describe "nested" do
+    it "gets the mailer after setting it with a string" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "Another Crazy Name Mailer Test" do
+  tests TestTestMailer
+
+  describe "nested" do
+    it "gets the mailer after setting it manually" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "Another Crazy Symbol Name Mailer Test" do
+  tests :test_test_mailer
+
+  describe "nested" do
+    it "gets the mailer after setting it with a symbol" do
+      assert_equal TestTestMailer, self.class.mailer_class
+    end
+  end
+end
+
+describe "Another Crazy String Name Mailer Test" do
+  tests 'test_test_mailer'
+
+  it "gets the mailer after setting it with a string" do
+    assert_equal TestTestMailer, self.class.mailer_class
+  end
+end