cmd/info: Add test for --json=v2

Library/Homebrew/test/cmd/info_spec.rb

@@ -17,6 +17,15 @@ describe "brew info", :integration_test do
       .and not_to_output.to_stderr
       .and be_a_success
   end
+
+  it "prints as json with the --json=v2 flag" do
+    setup_test_formula "testball"
+
+    expect { brew "info", "testball", "--json=v2" }
+      .to output(a_json_string).to_stdout
+      .and not_to_output.to_stderr
+      .and be_a_success
+  end
 end
 
 describe Homebrew do