minitest-pretty_diff

Monkey-patches MiniTest::Assertions#mu_pp to pretty-print hashes and arrays before diffing them. This makes it much easier to spot the differences between nested structures.

Usage

Just require the gem, and use MiniTest's assertions like before.

Before

MiniTest::Assertion
--- expected
+++ actual
@@ -1 +1 @@
-{"widget"=>{"debug"=>"on", "window"=>{"title"=>"Sample Konfabulator W
idget", "name"=>"main_window", "width"=>500, "height"=>500}, "image"=>{"src"=>"I
mages/Sun.png", "name"=>"sun1", "hOffset"=>250, "vOffset"=>250, "alignment"=>"ce
nter"}, "text"=>{"data"=>"Click Here", "size"=>36, "style"=>"bold", "name"=>"tex
t1", "hOffset"=>250, "vOffset"=>100, "alignment"=>"center", "onMouseUp"=>"sun1.o
pacity = (sun1.opacity / 100) * 90;"}}}
+{"widget"=>{"debug"=>"on", "window"=>{"title"=>"Sample Konfabulator W
idget", "name"=>"main_window", "width"=>500, "height"=>nil}, "image"=>{"src"=>"I
mages/Sun.png", "name"=>"sun1", "hOffset"=>250, "vOffset"=>250, "alignment"=>"le
ft"}, "text"=>{"data"=>"Click Here", "size"=>36, "style"=>"bold", "name"=>"text1
", "hOffset"=>250, "vOffset"=>100, "alignment"=>"center", "onMouseUp"=>"sun1.opa
city = (sun1.opacity / 100) * 90;"}}}

After

MiniTest::Assertion
--- expected
+++ actual
@@ -2,7 +2,7 @@
   "widget": {
     "debug": "on",
     "image": {
-      "alignment": "center",
+      "alignment": "left",
       "hOffset": 250,
       "name": "sun1",
       "src": "Images/Sun.png",
@@ -19,7 +19,7 @@
       "vOffset": 100
     },
     "window": {
-      "height": 500,
+      "height": null,
       "name": "main_window",
       "title": "Sample Konfabulator Widget",
       "width": 500

Installation

gem install minitest-pretty_diff # duh

Rails

group :test do
  gem "minitest-pretty_diff"
end

Requirements

This thing requires Ruby 1.9.2 or higher, because it uses the JSON module to pretty-print things. The PP class is available in older versions, but the output isn't as readable.

License

[minitest-pretty_diff] repo is free software, available under [the MIT license] license.