diff --git a/spec/options.spec.js b/spec/options.spec.js
index 617d9e4..8b87f15 100644
--- a/spec/options.spec.js
+++ b/spec/options.spec.js
@@ -881,7 +881,7 @@ describe('Ajv Options', function () {
         }
       });
 
-      it.skip('should throw during validation if unknown format is used via $data', function() {
+      it.skip('should fail validation if unknown format is used via $data', function() {
         test(new Ajv({v5: true, unknownFormats: true}));
 
         function test(ajv) {
@@ -897,9 +897,7 @@ describe('Ajv Options', function () {
           validate({foo: '20161016', bar: 'date'}) .should.equal(false);
           validate({foo: '20161016'}) .should.equal(true);
 
-          should.throw(function() {
-            validate({foo: '2016-10-16', bar: 'unknown'});
-          });
+          validate({foo: '2016-10-16', bar: 'unknown'}) .should.equal(false);
         }
       });
     });
@@ -967,10 +965,7 @@ describe('Ajv Options', function () {
           validate({foo: '20161016'}) .should.equal(true);
 
           validate({foo: '2016-10-16', bar: 'allowed'}) .should.equal(true);
-
-          should.throw(function() {
-            validate({foo: '2016-10-16', bar: 'unknown'});
-          });
+          validate({foo: '2016-10-16', bar: 'unknown'}) .should.equal(false);
         }
       });
     });
diff --git a/spec/schema-tests.spec.js b/spec/schema-tests.spec.js
index 8a7b17f..117bd99 100644
--- a/spec/schema-tests.spec.js
+++ b/spec/schema-tests.spec.js
@@ -6,7 +6,7 @@ var jsonSchemaTest = require('json-schema-test')
   , suite = require('./brower_test_suite')
   , after = require('./after_test');
 
-var instances = getAjvInstances(options);
+var instances = getAjvInstances(options, {unknownFormats: ['allowedUnknown']});
 
 var remoteRefs = {
   'http://localhost:1234/integer.json': require('./JSON-Schema-Test-Suite/remotes/integer.json'),
diff --git a/spec/tests/rules/format.json b/spec/tests/rules/format.json
index cb0bab8..ec15076 100644
--- a/spec/tests/rules/format.json
+++ b/spec/tests/rules/format.json
@@ -1,12 +1,12 @@
 [
   {
-    "description": "unknown format is always valid",
+    "description": "whitelisted unknown format is valid",
     "schema": {
-      "format": "unknownformat"
+      "format": "allowedUnknown"
     },
     "tests": [
       {
-        "description": "anything is valid",
+        "description": "any string is valid",
         "data": "any value",
         "valid": true
       }
diff --git a/spec/tests/schemas/advanced.json b/spec/tests/schemas/advanced.json
index f5d4ba2..12e94fc 100644
--- a/spec/tests/schemas/advanced.json
+++ b/spec/tests/schemas/advanced.json
@@ -72,7 +72,7 @@
                                 "server": {
                                     "type": "string",
                                     "anyOf": [
-                                        { "format": "host-name" },
+                                        { "format": "hostname" },
                                         { "format": "ipv4" },
                                         { "format": "ipv6" }
                                     ]
diff --git a/spec/v5.spec.js b/spec/v5.spec.js
index 9d21a8e..2044095 100644
--- a/spec/v5.spec.js
+++ b/spec/v5.spec.js
@@ -6,7 +6,7 @@ var jsonSchemaTest = require('json-schema-test')
   , suite = require('./brower_test_suite')
   , after = require('./after_test');
 
-var instances = getAjvInstances(options, { v5: true });
+var instances = getAjvInstances(options, { v5: true, unknownFormats: ['allowedUnknown'] });
 
 
 jsonSchemaTest(instances, {
diff --git a/spec/v5/formatMaximum.json b/spec/v5/formatMaximum.json
index 3c3864e..9e0e6c9 100644
--- a/spec/v5/formatMaximum.json
+++ b/spec/v5/formatMaximum.json
@@ -204,14 +204,14 @@
     ]
   },
   {
-    "description": "formatMaximum is valid with unknown format",
+    "description": "formatMaximum is valid with whitelisted unknown format",
     "schema": {
-      "format": "unknown",
+      "format": "allowedUnknown",
       "formatMaximum": "2015"
     },
     "tests": [
       {
-        "description": "always valid",
+        "description": "valid string",
         "data": "2016",
         "valid": true
       }