Format Failure Message JSON

This commit modifies the RSpec Matcher to use
[`JSON.pretty_generate`][docs] to improve the formatting of JSON bodies
and schemata that appear in failure messages.

Additionally, the `json-schema` provided error messages have been moved
to the top of the failure messages, so that the reasons for failure
appear above (potentially lengthy) JSON bodies.

[docs]: http://ruby-doc.org/stdlib-2.0.0/libdoc/json/rdoc/JSON.html#method-i-pretty_generate

NEWS.md

@@ -1,6 +1,8 @@
 master
 ======
 
+* Use `JSON.pretty_generate` to format error messages.
+
 0.6.0
 =====
 

lib/json_matchers/rspec.rb

@@ -12,38 +12,42 @@ def initialize(schema_name, **options)
 
  def failure_message(response)
  <<-FAIL.strip_heredoc
- expected
+ #{validation_failure_message}
 
- #{response.body}
+ ---
 
- to match schema "#{schema_name}":
+ expected
 
- #{schema_body}
+ #{pretty_json(response.body)}
 
- ---
+ to match schema "#{schema_name}":
 
- #{validation_failure_message}
+ #{pretty_json(schema_body)}
 
  FAIL
  end
 
  def failure_message_when_negated(response)
  <<-FAIL.strip_heredoc
- expected
+ #{validation_failure_message}
 
- #{response.body}
+ ---
 
- not to match schema "#{schema_name}":
+ expected
 
- #{schema_body}
+ #{pretty_json(response.body)}
 
- ---
+ not to match schema "#{schema_name}":
 
- #{validation_failure_message}
+ #{pretty_json(schema_body)}
 
  FAIL
  end
 
+ def pretty_json(json_string)
+ JSON.pretty_generate(JSON.parse(json_string.to_s))
+ end
+
  def schema_path
  JsonMatchers.path_to_schema(schema_name)
  end

spec/json_matchers/match_response_schema_spec.rb

@@ -72,15 +72,15 @@
 
  expect {
  expect(response_for("bar" => 5)).to match_response_schema("foo")
- }.to raise_error(/{"bar":5}/)
+ }.to raise_formatted_error(%{{ "bar": 5 }})
  end
 
  it "contains the body in the failure message when negated" do
  create_schema("foo", { "type" => "array" })
 
  expect {
  expect(response_for([])).not_to match_response_schema("foo")
- }.to raise_error(/\[\]/)
+ }.to raise_formatted_error("[ ]")
  end
 
  it "contains the schema in the failure message" do
@@ -89,7 +89,7 @@
 
  expect {
  expect(response_for("bar" => 5)).to match_response_schema("foo")
- }.to raise_error(/#{schema.to_json}/)
+ }.to raise_formatted_error(%{{ "type": "array" }})
  end
 
  it "contains the schema in the failure message when negated" do
@@ -98,7 +98,7 @@
 
  expect {
  expect(response_for([])).not_to match_response_schema("foo")
- }.to raise_error(/#{schema.to_json}/)
+ }.to raise_formatted_error(%{{ "type": "array" }})
  end
 
  it "does not fail when the schema matches" do
@@ -129,4 +129,10 @@
  expect(valid_response).to match_response_schema("collection")
  expect(invalid_response).not_to match_response_schema("collection")
  end
+
+ def raise_formatted_error(error_message)
+ raise_error do |error|
+ expect(error.message.squish).to include(error_message)
+ end
+ end
 end