Add specs for pretty print JSON

They only check that the response includes `\n`, which should not happen
otherwise.

spec/unit/endpoint/builds_spec.rb

@@ -1,5 +1,42 @@
 require 'spec_helper'
 
 describe Travis::Api::App::Endpoint::Builds do
-  it 'has to be tested'
+  include Travis::Testing::Stubs
+
+  it 'works with default options' do
+    get('/repos.json', {}).should be_ok
+  end
+
+  context '/repos.json is requested' do
+    before :each do
+      @plain_response_body = get('/repos.json').body
+    end
+
+    context 'when `pretty=true` is given' do
+      it 'prints pretty formatted data' do
+        response = get('/repos.json?pretty=true')
+        response.should be_ok
+        response.body.should_not eq(@plain_response_body)
+        response.body.should match(/\n/)
+      end
+    end
+
+    context 'when `pretty=1` is given' do
+      it 'prints pretty formatted data' do
+        response = get('/repos.json?pretty=1')
+        response.should be_ok
+        response.body.should_not eq(@plain_response_body)
+        response.body.should match(/\n/)
+      end
+    end
+
+    context 'when `pretty=bogus` is given' do
+      it 'prints plain-formatted data' do
+        response = get('/repos.json?pretty=bogus')
+        response.should be_ok
+        response.body.should eq(@plain_response_body)
+      end
+    end
+  end
+  
 end