Convert brew irb test to spec.

Library/Homebrew/cmd/irb.rb

@@ -12,6 +12,7 @@ class Symbol
     Formulary.factory(to_s, *args)
   end
 end
+
 class String
   def f(*args)
     Formulary.factory(self, *args)

Library/Homebrew/test/cmd/irb_spec.rb

@@ -0,0 +1,24 @@
+describe "brew irb", :integration_test do
+  it "starts an interactive Homebrew shell session" do
+    setup_test_formula "testball"
+
+    irb_test = HOMEBREW_TEMP/"irb-test.rb"
+    irb_test.write <<-EOS.undent
+      "testball".f
+      :testball.f
+      exit
+    EOS
+
+    expect { brew "irb", irb_test }
+      .to output(/Interactive Homebrew Shell/).to_stdout
+      .and not_to_output.to_stderr
+      .and be_a_success
+  end
+
+  specify "--examples" do
+    expect { brew "irb", "--examples" }
+      .to output(/'v8'\.f # => instance of the v8 formula/).to_stdout
+      .and not_to_output.to_stderr
+      .and be_a_success
+  end
+end

Library/Homebrew/test/irb_test.rb

@@ -1,19 +0,0 @@
-require "testing_env"
-
-class IntegrationCommandTestIrb < IntegrationCommandTestCase
-  def test_irb
-    assert_match "'v8'.f # => instance of the v8 formula",
-      cmd("irb", "--examples")
-
-    setup_test_formula "testball"
-
-    irb_test = HOMEBREW_TEMP/"irb-test.rb"
-    irb_test.write <<-EOS.undent
-      "testball".f
-      :testball.f
-      exit
-    EOS
-
-    assert_match "Interactive Homebrew Shell", cmd("irb", irb_test)
-  end
-end