Header name is case insensitive in the schema definition (#816)

* Add failing test

* Fix the simplest case

* Only if properties is set. Link to rfc

* Check for own properties in loops

lib/validation.js

@@ -29,7 +29,22 @@ function build (context, compile, schemas) {
   context.schema = schemas.resolveRefs(context.schema)
 
   if (context.schema.headers) {
-    context[headersSchema] = compile(context.schema.headers)
+    // The header keys are case insensitive
+    //  https://tools.ietf.org/html/rfc2616#section-4.2
+    const headers = context.schema.headers
+    const headersSchemaLowerCase = {}
+    for (const k in headers) {
+      if (headers.hasOwnProperty(k) !== true) continue
+      headersSchemaLowerCase[k] = headers[k]
+    }
+    if (headers.properties) {
+      const properties = headers.properties
+      for (const k in properties) {
+        if (properties.hasOwnProperty(k) !== true) continue
+        headersSchemaLowerCase.properties[k.toLowerCase()] = properties[k]
+      }
+    }
+    context[headersSchema] = compile(headersSchemaLowerCase)
   }
 
   if (context.schema.response) {

test/get.test.js

@@ -81,6 +81,9 @@ const headersSchema = {
       properties: {
         'x-test': {
           type: 'number'
+        },
+        'Y-Test': {
+          type: 'number'
         }
       }
     }
@@ -257,14 +260,16 @@ fastify.listen(0, err => {
     sget({
       method: 'GET',
       headers: {
-        'x-test': 1
+        'x-test': '1',
+        'Y-Test': '3'
       },
+      json: true,
       url: 'http://localhost:' + fastify.server.address().port + '/headers'
     }, (err, response, body) => {
       t.error(err)
       t.strictEqual(response.statusCode, 200)
-      t.strictEqual(response.headers['content-length'], '' + body.length)
-      t.strictEqual(JSON.parse(body)['x-test'], 1)
+      t.strictEqual(body['x-test'], 1)
+      t.strictEqual(body['y-test'], 3)
     })
   })