Convert Version test to spec.

Library/Homebrew/cask/spec/cask/cli/version_spec.rb

@@ -0,0 +1,11 @@
+require "spec_helper"
+
+describe "brew cask --version" do
+  it "respects the --version argument" do
+    expect {
+      expect {
+        Hbc::CLI::NullCommand.new("--version").run
+      }.not_to output.to_stderr
+    }.to output(Hbc.full_version).to_stdout
+  end
+end

Library/Homebrew/cask/test/cask/cli/version_test.rb

@@ -1,9 +0,0 @@
-require "test_helper"
-
-describe "brew cask --version" do
-  it "respects the --version argument" do
-    lambda {
-      Hbc::CLI::NullCommand.new("--version").run
-    }.must_output Hbc.full_version
-  end
-end