diff --git a/lib/fog/compute/aws.rb b/lib/fog/compute/aws.rb
index df3eabf99..2b24f18f1 100644
--- a/lib/fog/compute/aws.rb
+++ b/lib/fog/compute/aws.rb
@@ -141,12 +141,12 @@ module Fog
 
           @aws_access_key_id = options[:aws_access_key_id]
 
-          unless ['ap-northeast-1', 'ap-southeast-1', 'eu-west-1', 'us-east-1', 'us-west-1'].include?(options[:region])
-            raise ArgumentError, "Unknown region: #{options[:region].inspect}"
-          end
-
           @region = options[:region] || 'us-east-1'
 
+          unless ['ap-northeast-1', 'ap-southeast-1', 'eu-west-1', 'us-east-1', 'us-west-1'].include?(@region)
+            raise ArgumentError, "Unknown region: #{@region.inspect}"
+          end
+
           @data = self.class.data[@region][@aws_access_key_id]
           @owner_id = @data[:owner_id]
         end
diff --git a/lib/fog/compute/requests/aws/get_password_data.rb b/lib/fog/compute/requests/aws/get_password_data.rb
index 30ca950c6..8a6298a0b 100644
--- a/lib/fog/compute/requests/aws/get_password_data.rb
+++ b/lib/fog/compute/requests/aws/get_password_data.rb
@@ -33,7 +33,19 @@ module Fog
       class Mock
 
         def get_password_data(instance_id)
-          Fog::Mock.not_implemented
+          response = Excon::Response.new
+          if instance = @data[:instances][instance_id]
+            response.status = 200
+            response.body = {
+              'instanceId'   => instance_id,
+              'passwordData' => nil,
+              'requestId'    => Fog::AWS::Mock.request_id,
+              'timestamp'    => Time.now
+            }
+            response
+          else;
+            raise Fog::AWS::Compute::NotFound.new("The instance ID '#{instance_id}' does not exist")
+          end
         end
 
       end
diff --git a/lib/fog/providers/aws.rb b/lib/fog/providers/aws.rb
index b7192d821..8ec5bb68b 100644
--- a/lib/fog/providers/aws.rb
+++ b/lib/fog/providers/aws.rb
@@ -1,5 +1,6 @@
 require 'fog/core'
 require 'fog/core/parser'
+require 'openssl' # For RSA key pairs
 
 module Fog
   module AWS
@@ -44,7 +45,7 @@ module Fog
     def self.escape(string)
       string.gsub( /([^-a-zA-Z0-9_.~]+)/n ) { |match| '%' + match.unpack( 'H2' * match.size ).join( '%' ).upcase }
     end
-    
+
     def self.signed_params(params, options = {})
       params.merge!({
         'AWSAccessKeyId'    => options[:aws_access_key_id],
@@ -140,13 +141,7 @@ module Fog
       end
 
       def self.key_material
-        key_material = ['-----BEGIN RSA PRIVATE KEY-----']
-        20.times do
-          key_material << Fog::Mock.random_base64(76)
-        end
-        key_material << Fog::Mock.random_base64(67) + '='
-        key_material << '-----END RSA PRIVATE KEY-----'
-        key_material.join("\n")
+        OpenSSL::PKey::RSA.generate(1024).to_s
       end
 
       def self.owner_id
diff --git a/tests/compute/requests/aws/instance_tests.rb b/tests/compute/requests/aws/instance_tests.rb
index 6417fa98e..9ca5b6c69 100644
--- a/tests/compute/requests/aws/instance_tests.rb
+++ b/tests/compute/requests/aws/instance_tests.rb
@@ -60,7 +60,7 @@ Shindo.tests('AWS::Compute | instance requests', ['aws']) do
 
   @get_password_data_format = {
     'instanceId'   => String,
-    'passwordData' => String,
+    'passwordData' => Fog::Nullable::String,
     'requestId'    => String,
     'timestamp'    => Time
   }
@@ -119,15 +119,18 @@ Shindo.tests('AWS::Compute | instance requests', ['aws']) do
     end
 
     tests("#get_password_data('#{@instance_id}')").formats(@get_password_data_format) do
-      pending if Fog.mock?
-      result = nil
-      Fog.wait_for do
-         result = AWS[:compute].get_password_data(@instance_id).body
-         !result['passwordData'].nil?
-      end
+      result = AWS[:compute].get_password_data(@instance_id).body
 
       tests("key can decrypt passwordData").returns(true) do
-        decoded_password = Base64.decode64(result['passwordData'])
+
+        pending if Fog.mocking?
+
+        password_data = result['passwordData']
+        Fog.wait_for do
+          password_data ||= AWS[:compute].get_password_data(@instance_id).body['passwordData']
+        end
+
+        decoded_password = Base64.decode64(password_data)
         pkey = OpenSSL::PKey::RSA.new(key.private_key)
         String === pkey.private_decrypt(decoded_password)
       end
diff --git a/tests/compute/requests/aws/key_pair_tests.rb b/tests/compute/requests/aws/key_pair_tests.rb
index 655f00920..a4f709dba 100644
--- a/tests/compute/requests/aws/key_pair_tests.rb
+++ b/tests/compute/requests/aws/key_pair_tests.rb
@@ -21,7 +21,7 @@ Shindo.tests('AWS::Compute | key pair requests', ['aws']) do
 
     tests("#create_key_pair('#{@key_pair_name}')").formats(@keypair_format.merge({'keyMaterial' => String})) do
       body = AWS[:compute].create_key_pair(@key_pair_name).body
-      tests("private key is valid RSA key").returns(OpenSSL::PKey::RSA) do
+      tests("key material").returns(OpenSSL::PKey::RSA, "is a valid private RSA key") do
         OpenSSL::PKey::RSA.new(body['keyMaterial']).class
       end
       body
diff --git a/tests/compute/requests/aws/volume_tests.rb b/tests/compute/requests/aws/volume_tests.rb
index d267fdf52..610ce8c9f 100644
--- a/tests/compute/requests/aws/volume_tests.rb
+++ b/tests/compute/requests/aws/volume_tests.rb
@@ -22,12 +22,12 @@ Shindo.tests('AWS::Compute | volume requests', ['aws']) do
   @volumes_format = {
     'volumeSet' => [{
       'availabilityZone'  => String,
-      'attachmentSet'     => [],
+      'attachmentSet'     => Array,
       'createTime'        => Time,
       'size'              => Integer,
       'snapshotId'        => Fog::Nullable::String,
       'status'            => String,
-      'tagSet'            => {},
+      'tagSet'            => Hash,
       'volumeId'          => String
     }],
     'requestId' => String