Better validation error messages for headers

src/utils/tv4-to-headers-message.coffee

@@ -0,0 +1,21 @@
+module.exports = (message) ->
+  if message.indexOf("Missing required property:") > 1
+    headerName = message.split("Missing required property: ")[1]
+    newMessage = "Header '#{headerName}' is missing"
+
+  else if message.indexOf("No enum match for: ") > 1
+    splitted = message.split '\' No enum match for: "'
+
+    headerName = splitted[0]
+    headerName = headerName.replace(/^At '\//, '')
+
+    headerValue = splitted[1]
+    headerValue = headerValue.replace(/"$/, '')
+
+
+    newMessage = "Header '#{headerName}' doesn't have value '#{headerValue}'"
+
+  else
+    throw new Error 'Unknown tv4 error message can\'t convert to headers message.'
+
+  return newMessage

src/validators/headers-json-example.coffee

@@ -1,8 +1,11 @@
 errors          = require '../errors'
 {JsonSchema}   = require './json-schema'
-{SchemaV4Generator, SchemaV4Properties} = require('../utils/schema-v4-generator')
+{SchemaV4Generator, SchemaV4Properties} = require '../utils/schema-v4-generator'
+tv4ToHeadersMessage = require '../utils/tv4-to-headers-message'
+
 jsonPointer = require 'json-pointer'
-type        = require 'is-type'
+type = require 'is-type'
+
 
 # Checks data, prepares validator and validates request or response headers against given expected headers or json schema
 # @author Peter Grilli <tully@apiary.io>
@@ -34,6 +37,14 @@ class HeadersJsonExample extends JsonSchema
 
     super @real, @schema
 
+  validate: ->
+
+    result = super()
+    if result.length > 0
+      for i in [0..(result.length - 1)]
+        result[i]['message'] = tv4ToHeadersMessage result[i]['message']
+
+    result
   #@private
   prepareHeaders: (headers) ->
     if not type.object(headers)

src/validators/json-schema.coffee

@@ -123,7 +123,6 @@ class JsonSchema
 
     unless dataIsTheSame and schemaIsTheSame
       @output = @validatePrivate()
-
     return @output
 
   evaluateOutputToResults: (data) ->

test/unit/utils/tv4-to-headers-message-test.coffee

@@ -0,0 +1,23 @@
+{assert} = require 'chai'
+tv4ToHeadersMessage = require '../../../src/utils/tv4-to-headers-message'
+
+describe 'tv4ToHeadersMessages()', ->
+
+  describe 'when message for missing header', ->
+    it 'should return message with right text', ->
+      tv4Message = 'At \'/header2\' Missing required property: header2'
+      message = tv4ToHeadersMessage(tv4Message)
+      assert.equal message, "Header 'header2' is missing"
+
+  describe 'when message for different value', ->
+    it 'should return message with right text', ->
+      tv4Message = 'At \'/content-type\' No enum match for: "application/fancy-madiatype"'
+      message = tv4ToHeadersMessage(tv4Message)
+      assert.equal message, "Header 'content-type' doesn't have value 'application/fancy-madiatype'"
+
+  describe 'when unknonw message', ->
+    it 'should throw an error', ->
+      fn = () ->
+        tv4ToHeadersMessage("String does not match pattern: {pattern}")
+      assert.throws fn
+

test/unit/validators/headers-json-example-validator-test.coffee

@@ -1,5 +1,5 @@
 {assert} = require('chai')
-{HeadersJsonExample} = require('../../../src/validators/headers-json-example')
+{HeadersJsonExample} = require '../../../src/validators/headers-json-example'
 fixtures = require '../../fixtures'
 shared = require '../support/amanda-to-gavel-shared'
 
@@ -53,24 +53,35 @@ describe 'HeadersJsonExample', ->
           assert.lengthOf result, 0
 
     describe 'when key is missing in provided headers', ->
-      before ->
+      beforeEach ->
         headersValidator = new HeadersJsonExample fixtures.sampleHeadersMissing , fixtures.sampleHeaders
       describe 'and i run validate()', ->
         it "should return 1 error", ->
           result = headersValidator.validate()
           assert.equal result.length, 1
 
+        it 'should have beautiful error message', ->
+          result = headersValidator.validate()
+          assert.equal result[0].message, "Header 'header2' is missing"
+
     describe 'when value of content negotiation header in provided headers differs', ->
-      before ->
+      beforeEach ->
         headersValidator = new HeadersJsonExample fixtures.sampleHeadersDiffers , fixtures.sampleHeaders
+
       describe 'and i run validate()', ->
         it "should return 1 errors", ->
           result = headersValidator.validate()
           assert.equal result.length, 1
 
+        it 'should have beautiful error message', ->
+          result = headersValidator.validate()
+          console.log result
+          assert.equal result[0].message, "Header 'content-type' doesn't have value 'application/fancy-madiatype'"
+
     describe 'when key is added to provided headers', ->
       before ->
         headersValidator = new HeadersJsonExample fixtures.sampleHeadersAdded , fixtures.sampleHeaders
+
       describe 'and i run validate()', ->
         it "shouldn't return any errors", ->
           result = headersValidator.validate()
@@ -84,14 +95,16 @@ describe 'HeadersJsonExample', ->
           result = headersValidator.validate()
           assert.equal result.length, 2
 
-    describe 'when non content negotiation header heeader values differs', ->
+    describe 'when non content negotiation header header values differs', ->
       before ->
         headersValidator = new HeadersJsonExample fixtures.sampleHeadersWithNonContentNegotiationChanged,  fixtures.sampleHeadersNonContentNegotiation
+
       describe 'and i run validate()', ->
         it "shouldn't return any errors", ->
           result = headersValidator.validate()
           assert.equal result.length, 0
 
+
   describe '#validate()', () ->
     output = null
     before () ->