Merge pull request #13 from tbetbetbe/ruby-auth-add-user-creds

Ruby auth add user creds

lib/googleauth.rb

@@ -27,8 +27,13 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-require 'googleauth/service_account'
+require 'multi_json'
+require 'stringio'
+
+require 'googleauth/credentials_loader'
 require 'googleauth/compute_engine'
+require 'googleauth/service_account'
+require 'googleauth/user_refresh'
 
 module Google
   # Module Auth provides classes that provide Google-specific authorization
@@ -40,6 +45,29 @@ https://developers.google.com/accounts/docs/application-default-credentials
 for more information
 END
 
+    # DefaultCredentials is used to preload the credentials file, to determine
+    # which type of credentials should be loaded.
+    class DefaultCredentials
+      extend CredentialsLoader
+
+      # override CredentialsLoader#make_creds to use the class determined by
+      # loading the json.
+      def self.make_creds(scope, json_key_io)
+        json_key, clz = determine_creds_class(json_key_io)
+        clz.new(scope, StringIO.new(MultiJson.dump(json_key)))
+      end
+
+      # Reads the input json and determines which creds class to use.
+      def self.determine_creds_class(json_key_io)
+        json_key = MultiJson.load(json_key_io.read)
+        fail "the json is missing the #{key} field" unless json_key.key?('type')
+        type = json_key['type']
+        return json_key, ServiceAccountCredentials if type == 'service_account'
+        return [json_key, UserRefreshCredentials] if type == 'authorized_user'
+        fail "credentials type '#{type}' is not supported"
+      end
+    end
+
     # Obtains the default credentials implementation to use in this
     # environment.
     #
@@ -53,9 +81,9 @@ END
     # @param scope [string|array] the scope(s) to access
     # @param options [hash] allows override of the connection being used
     def get_application_default(scope, options = {})
-      creds = ServiceAccountCredentials.from_env(scope)
+      creds = DefaultCredentials.from_env(scope)
       return creds unless creds.nil?
-      creds = ServiceAccountCredentials.from_well_known_path(scope)
+      creds = DefaultCredentials.from_well_known_path(scope)
       return creds unless creds.nil?
       fail NOT_FOUND_ERROR unless GCECredentials.on_gce?(options)
       GCECredentials.new

lib/googleauth/credentials_loader.rb

@@ -0,0 +1,93 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'memoist'
+require 'rbconfig'
+
+module Google
+  # Module Auth provides classes that provide Google-specific authorization
+  # used to access Google APIs.
+  module Auth
+    # CredentialsLoader contains the behaviour used to locate and find default
+    # credentials files on the file system.
+    module CredentialsLoader
+      extend Memoist
+      ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS'
+      NOT_FOUND_ERROR =
+        "Unable to read the credential file specified by #{ENV_VAR}"
+      WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json'
+      WELL_KNOWN_ERROR = 'Unable to read the default credential file'
+
+      # determines if the current OS is windows
+      def windows?
+        RbConfig::CONFIG['host_os'] =~ /Windows|mswin/
+      end
+      memoize :windows?
+
+      # make_creds proxies the construction of a credentials instance
+      #
+      # By default, it calls #new on the current class, but this behaviour can
+      # be modified, allowing different instances to be created.
+      def make_creds(*args)
+        new(*args)
+      end
+
+      # Creates an instance from the path specified in an environment
+      # variable.
+      #
+      # @param scope [string|array] the scope(s) to access
+      def from_env(scope)
+        return nil unless ENV.key?(ENV_VAR)
+        path = ENV[ENV_VAR]
+        fail 'file #{path} does not exist' unless File.exist?(path)
+        File.open(path) do |f|
+          return make_creds(scope, f)
+        end
+      rescue StandardError => e
+        raise "#{NOT_FOUND_ERROR}: #{e}"
+      end
+
+      # Creates an instance from a well known path.
+      #
+      # @param scope [string|array] the scope(s) to access
+      def from_well_known_path(scope)
+        home_var, base = windows? ? 'APPDATA' : 'HOME', WELL_KNOWN_PATH
+        root = ENV[home_var].nil? ? '' : ENV[home_var]
+        base = File.join('.config', base) unless windows?
+        path = File.join(root, base)
+        return nil unless File.exist?(path)
+        File.open(path) do |f|
+          return make_creds(scope, f)
+        end
+      rescue StandardError => e
+        raise "#{WELL_KNOWN_ERROR}: #{e}"
+      end
+    end
+  end
+end

lib/googleauth/service_account.rb

@@ -28,18 +28,8 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require 'googleauth/signet'
-require 'memoist'
+require 'googleauth/credentials_loader'
 require 'multi_json'
-require 'openssl'
-require 'rbconfig'
-
-# Reads the private key and client email fields from service account JSON key.
-def read_json_key(json_key_io)
-  json_key = MultiJson.load(json_key_io.read)
-  fail 'missing client_email' unless json_key.key?('client_email')
-  fail 'missing private_key' unless json_key.key?('private_key')
-  [json_key['private_key'], json_key['client_email']]
-end
 
 module Google
   # Module Auth provides classes that provide Google-specific authorization
@@ -53,52 +43,16 @@ module Google
     #
     # cf [Application Default Credentials](http://goo.gl/mkAHpZ)
     class ServiceAccountCredentials < Signet::OAuth2::Client
-      ENV_VAR = 'GOOGLE_APPLICATION_CREDENTIALS'
-      NOT_FOUND_ERROR =
-        "Unable to read the credential file specified by #{ENV_VAR}"
       TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'
-      WELL_KNOWN_PATH = 'gcloud/application_default_credentials.json'
+      extend CredentialsLoader
-      WELL_KNOWN_ERROR = 'Unable to read the default credential file'
 
-      class << self
+      # Reads the private key and client email fields from the service account
-        extend Memoist
+      # JSON key.
-
+      def self.read_json_key(json_key_io)
-        # determines if the current OS is windows
+        json_key = MultiJson.load(json_key_io.read)
-        def windows?
+        fail 'missing client_email' unless json_key.key?('client_email')
-          RbConfig::CONFIG['host_os'] =~ /Windows|mswin/
+        fail 'missing private_key' unless json_key.key?('private_key')
-        end
+        [json_key['private_key'], json_key['client_email']]
-        memoize :windows?
-
-        # Creates an instance from the path specified in an environment
-        # variable.
-        #
-        # @param scope [string|array] the scope(s) to access
-        def from_env(scope)
-          return nil unless ENV.key?(ENV_VAR)
-          path = ENV[ENV_VAR]
-          fail 'file #{path} does not exist' unless File.exist?(path)
-          File.open(path) do |f|
-            return new(scope, f)
-          end
-        rescue StandardError => e
-          raise "#{NOT_FOUND_ERROR}: #{e}"
-        end
-
-        # Creates an instance from a well known path.
-        #
-        # @param scope [string|array] the scope(s) to access
-        def from_well_known_path(scope)
-          home_var, base = windows? ? 'APPDATA' : 'HOME', WELL_KNOWN_PATH
-          root = ENV[home_var].nil? ? '' : ENV[home_var]
-          base = File.join('.config', base) unless windows?
-          path = File.join(root, base)
-          return nil unless File.exist?(path)
-          File.open(path) do |f|
-            return new(scope, f)
-          end
-        rescue StandardError => e
-          raise "#{WELL_KNOWN_ERROR}: #{e}"
-        end
       end
 
       # Initializes a ServiceAccountCredentials.
@@ -106,9 +60,9 @@ module Google
       # @param scope [string|array] the scope(s) to access
       # @param json_key_io [IO] an IO from which the JSON key can be read
       def initialize(scope, json_key_io)
-        private_key, client_email = read_json_key(json_key_io)
+        private_key, client_email = self.class.read_json_key(json_key_io)
         super(token_credential_uri: TOKEN_CRED_URI,
-              audience: TOKEN_CRED_URI,  # TODO: confirm this
+              audience: TOKEN_CRED_URI,
               scope: scope,
               issuer: client_email,
               signing_key: OpenSSL::PKey::RSA.new(private_key))

lib/googleauth/user_refresh.rb

@@ -0,0 +1,76 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'googleauth/signet'
+require 'googleauth/credentials_loader'
+require 'multi_json'
+
+module Google
+  # Module Auth provides classes that provide Google-specific authorization
+  # used to access Google APIs.
+  module Auth
+    # Authenticates requests using User Refresh credentials.
+    #
+    # This class allows authorizing requests from user refresh tokens.
+    #
+    # This the end of the result of a 3LO flow.  E.g, the end result of
+    # 'gcloud auth login' saves a file with these contents in well known
+    # location
+    #
+    # cf [Application Default Credentials](http://goo.gl/mkAHpZ)
+    class UserRefreshCredentials < Signet::OAuth2::Client
+      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'
+      extend CredentialsLoader
+
+      # Reads the client_id, client_secret and refresh_token fields from the
+      # JSON key.
+      def self.read_json_key(json_key_io)
+        json_key = MultiJson.load(json_key_io.read)
+        wanted = %w(client_id client_secret refresh_token)
+        wanted.each do |key|
+          fail "the json is missing the #{key} field" unless json_key.key?(key)
+        end
+        json_key
+      end
+
+      # Initializes a UserRefreshCredentials.
+      #
+      # @param scope [string|array] the scope(s) to access
+      # @param json_key_io [IO] an IO from which the JSON key can be read
+      def initialize(scope, json_key_io)
+        user_creds = self.class.read_json_key(json_key_io)
+        super(token_credential_uri: TOKEN_CRED_URI,
+              client_id: user_creds['client_id'],
+              client_secret: user_creds['client_secret'],
+              refresh_token: user_creds['refresh_token'],
+              scope: scope)
+      end
+    end
+  end
+end

spec/googleauth/get_application_default_spec.rb

@@ -38,7 +38,7 @@ require 'spec_helper'
 describe '#get_application_default' do
   before(:example) do
     @key = OpenSSL::PKey::RSA.new(2048)
-    @var_name = ServiceAccountCredentials::ENV_VAR
+    @var_name = CredentialsLoader::ENV_VAR
     @orig = ENV[@var_name]
     @home = ENV['HOME']
     @scope = 'https://www.googleapis.com/auth/userinfo.profile'
@@ -49,17 +49,7 @@ describe '#get_application_default' do
     ENV['HOME'] = @home unless @home == ENV['HOME']
   end
 
-  def cred_json_text
+  shared_examples 'it cannot load misconfigured credentials' do
-    cred_json = {
-      private_key_id: 'a_private_key_id',
-      private_key: @key.to_pem,
-      client_email: 'app@developer.gserviceaccount.com',
-      client_id: 'app.apps.googleusercontent.com',
-      type: 'service_account'
-    }
-    MultiJson.dump(cred_json)
-  end
-
     it 'fails if the GOOGLE_APPLICATION_CREDENTIALS path does not exist' do
       Dir.mktmpdir do |dir|
         key_path = File.join(dir, 'does-not-exist')
@@ -68,28 +58,6 @@ describe '#get_application_default' do
       end
     end
 
-  it 'succeeds if the GOOGLE_APPLICATION_CREDENTIALS file is valid' do
-    Dir.mktmpdir do |dir|
-      key_path = File.join(dir, 'my_cert_file')
-      FileUtils.mkdir_p(File.dirname(key_path))
-      File.write(key_path, cred_json_text)
-      ENV[@var_name] = key_path
-      expect(Google::Auth.get_application_default(@scope)).to_not be_nil
-    end
-  end
-
-  it 'succeeds with default file if GOOGLE_APPLICATION_CREDENTIALS is unset' do
-    ENV.delete(@var_name) unless ENV[@var_name].nil?
-    Dir.mktmpdir do |dir|
-      key_path = File.join(dir, '.config',
-                           ServiceAccountCredentials::WELL_KNOWN_PATH)
-      FileUtils.mkdir_p(File.dirname(key_path))
-      File.write(key_path, cred_json_text)
-      ENV['HOME'] = dir
-      expect(Google::Auth.get_application_default(@scope)).to_not be_nil
-    end
-  end
-
     it 'fails without default file or env if not on compute engine' do
       stubs = Faraday::Adapter::Test::Stubs.new do |stub|
         stub.get('/') do |_env|
@@ -111,6 +79,30 @@ describe '#get_application_default' do
       end
       stubs.verify_stubbed_calls
     end
+  end
+
+  shared_examples 'it can successfully load credentials' do
+    it 'succeeds if the GOOGLE_APPLICATION_CREDENTIALS file is valid' do
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, 'my_cert_file')
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV[@var_name] = key_path
+        expect(Google::Auth.get_application_default(@scope)).to_not be_nil
+      end
+    end
+
+    it 'succeeds with default file without GOOGLE_APPLICATION_CREDENTIALS' do
+      ENV.delete(@var_name) unless ENV[@var_name].nil?
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, '.config',
+                             CredentialsLoader::WELL_KNOWN_PATH)
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV['HOME'] = dir
+        expect(Google::Auth.get_application_default(@scope)).to_not be_nil
+      end
+    end
 
     it 'succeeds without default file or env if on compute engine' do
       stubs = Faraday::Adapter::Test::Stubs.new do |stub|
@@ -126,9 +118,83 @@ describe '#get_application_default' do
         c = Faraday.new do |b|
           b.adapter(:test, stubs)
         end
-      expect(Google::Auth.get_application_default(@scope,
+        creds = Google::Auth.get_application_default(
-                                                  connection: c)).to_not be_nil
+          @scope,
+          connection: c)
+        expect(creds).to_not be_nil
       end
       stubs.verify_stubbed_calls
     end
+  end
+
+  describe 'when credential type is service account' do
+    def cred_json_text
+      cred_json = {
+        private_key_id: 'a_private_key_id',
+        private_key: @key.to_pem,
+        client_email: 'app@developer.gserviceaccount.com',
+        client_id: 'app.apps.googleusercontent.com',
+        type: 'service_account'
+      }
+      MultiJson.dump(cred_json)
+    end
+
+    it_behaves_like 'it can successfully load credentials'
+    it_behaves_like 'it cannot load misconfigured credentials'
+  end
+
+  describe 'when credential type is authorized_user' do
+    def cred_json_text
+      cred_json = {
+        client_secret: 'privatekey',
+        refresh_token: 'refreshtoken',
+        client_id: 'app.apps.googleusercontent.com',
+        type: 'authorized_user'
+      }
+      MultiJson.dump(cred_json)
+    end
+
+    it_behaves_like 'it can successfully load credentials'
+    it_behaves_like 'it cannot load misconfigured credentials'
+  end
+
+  describe 'when credential type is unknown' do
+    def cred_json_text
+      cred_json = {
+        client_secret: 'privatekey',
+        refresh_token: 'refreshtoken',
+        client_id: 'app.apps.googleusercontent.com',
+        type: 'not_known_type'
+      }
+      MultiJson.dump(cred_json)
+    end
+
+    it 'fails if the GOOGLE_APPLICATION_CREDENTIALS file contains the creds' do
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, 'my_cert_file')
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV[@var_name] = key_path
+        blk = proc do
+          Google::Auth.get_application_default(@scope)
+        end
+        expect(&blk).to raise_error RuntimeError
+      end
+    end
+
+    it 'fails if the well known file contains the creds' do
+      ENV.delete(@var_name) unless ENV[@var_name].nil?
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, '.config',
+                             CredentialsLoader::WELL_KNOWN_PATH)
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV['HOME'] = dir
+        blk = proc do
+          Google::Auth.get_application_default(@scope)
+        end
+        expect(&blk).to raise_error RuntimeError
+      end
+    end
+  end
 end

spec/googleauth/service_account_spec.rb

@@ -42,6 +42,7 @@ require 'tmpdir'
 
 describe Google::Auth::ServiceAccountCredentials do
   ServiceAccountCredentials = Google::Auth::ServiceAccountCredentials
+  CredentialsLoader = Google::Auth::CredentialsLoader
 
   before(:example) do
     @key = OpenSSL::PKey::RSA.new(2048)
@@ -79,9 +80,10 @@ describe Google::Auth::ServiceAccountCredentials do
 
   describe '#from_env' do
     before(:example) do
-      @var_name = ServiceAccountCredentials::ENV_VAR
+      @var_name = CredentialsLoader::ENV_VAR
       @orig = ENV[@var_name]
       @scope = 'https://www.googleapis.com/auth/userinfo.profile'
+      @clz = ServiceAccountCredentials
     end
 
     after(:example) do
@@ -99,18 +101,17 @@ describe Google::Auth::ServiceAccountCredentials do
       Dir.mktmpdir do |dir|
         key_path = File.join(dir, 'does-not-exist')
         ENV[@var_name] = key_path
-        expect { sac.from_env(@scope) }.to raise_error
+        expect { @clz.from_env(@scope) }.to raise_error
       end
     end
 
     it 'succeeds when the GOOGLE_APPLICATION_CREDENTIALS file is valid' do
-      sac = ServiceAccountCredentials  # shortens name
       Dir.mktmpdir do |dir|
         key_path = File.join(dir, 'my_cert_file')
         FileUtils.mkdir_p(File.dirname(key_path))
         File.write(key_path, cred_json_text)
         ENV[@var_name] = key_path
-        expect(sac.from_env(@scope)).to_not be_nil
+        expect(@clz.from_env(@scope)).to_not be_nil
       end
     end
   end
@@ -119,6 +120,8 @@ describe Google::Auth::ServiceAccountCredentials do
     before(:example) do
       @home = ENV['HOME']
       @scope = 'https://www.googleapis.com/auth/userinfo.profile'
+      @known_path = CredentialsLoader::WELL_KNOWN_PATH
+      @clz = ServiceAccountCredentials
     end
 
     after(:example) do
@@ -131,13 +134,12 @@ describe Google::Auth::ServiceAccountCredentials do
     end
 
     it 'successfully loads the file when it is present' do
-      sac = ServiceAccountCredentials  # shortens name
       Dir.mktmpdir do |dir|
-        key_path = File.join(dir, '.config', sac::WELL_KNOWN_PATH)
+        key_path = File.join(dir, '.config', @known_path)
         FileUtils.mkdir_p(File.dirname(key_path))
         File.write(key_path, cred_json_text)
         ENV['HOME'] = dir
-        expect(sac.from_well_known_path(@scope)).to_not be_nil
+        expect(@clz.from_well_known_path(@scope)).to_not be_nil
       end
     end
   end

spec/googleauth/user_refresh_spec.rb

@@ -0,0 +1,170 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+spec_dir = File.expand_path(File.join(File.dirname(__FILE__)))
+$LOAD_PATH.unshift(spec_dir)
+$LOAD_PATH.uniq!
+
+require 'apply_auth_examples'
+require 'fileutils'
+require 'googleauth/user_refresh'
+require 'jwt'
+require 'multi_json'
+require 'openssl'
+require 'spec_helper'
+require 'tmpdir'
+
+describe Google::Auth::UserRefreshCredentials do
+  UserRefreshCredentials = Google::Auth::UserRefreshCredentials
+  CredentialsLoader = Google::Auth::CredentialsLoader
+
+  before(:example) do
+    @key = OpenSSL::PKey::RSA.new(2048)
+    @client = UserRefreshCredentials.new(
+        'https://www.googleapis.com/auth/userinfo.profile',
+        StringIO.new(cred_json_text))
+  end
+
+  def make_auth_stubs(opts = {})
+    access_token = opts[:access_token] || ''
+    Faraday::Adapter::Test::Stubs.new do |stub|
+      stub.post('/oauth2/v3/token') do |env|
+        params = Addressable::URI.form_unencode(env[:body])
+        want = %w(grant_type refresh_token)
+        expect(params.assoc('grant_type')).to eq(want)
+        build_access_token_json(access_token)
+      end
+    end
+  end
+
+  def cred_json_text(missing = nil)
+    cred_json = {
+      client_secret: 'privatekey',
+      client_id: 'client123',
+      refresh_token: 'refreshtoken',
+      type: 'authorized_user'
+    }
+    cred_json.delete(missing.to_sym) unless missing.nil?
+    MultiJson.dump(cred_json)
+  end
+
+  it_behaves_like 'apply/apply! are OK'
+
+  describe '#from_env' do
+    before(:example) do
+      @var_name = CredentialsLoader::ENV_VAR
+      @orig = ENV[@var_name]
+      @scope = 'https://www.googleapis.com/auth/userinfo.profile'
+      @clz = UserRefreshCredentials
+    end
+
+    after(:example) do
+      ENV[@var_name] = @orig unless @orig.nil?
+    end
+
+    it 'returns nil if the GOOGLE_APPLICATION_CREDENTIALS is unset' do
+      ENV.delete(@var_name) unless ENV[@var_name].nil?
+      expect(UserRefreshCredentials.from_env(@scope)).to be_nil
+    end
+
+    it 'fails if the GOOGLE_APPLICATION_CREDENTIALS path does not exist' do
+      ENV.delete(@var_name) unless ENV[@var_name].nil?
+      expect(UserRefreshCredentials.from_env(@scope)).to be_nil
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, 'does-not-exist')
+        ENV[@var_name] = key_path
+        expect { @clz.from_env(@scope) }.to raise_error
+      end
+    end
+
+    it 'fails if the GOOGLE_APPLICATION_CREDENTIALS path file is invalid' do
+      needed = %w(client_id client_secret refresh_token)
+      needed.each do |missing|
+        Dir.mktmpdir do |dir|
+          key_path = File.join(dir, 'my_cert_file')
+          FileUtils.mkdir_p(File.dirname(key_path))
+          File.write(key_path, cred_json_text(missing))
+          ENV[@var_name] = key_path
+          expect { @clz.from_env(@scope) }.to raise_error
+        end
+      end
+    end
+
+    it 'succeeds when the GOOGLE_APPLICATION_CREDENTIALS file is valid' do
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, 'my_cert_file')
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV[@var_name] = key_path
+        expect(@clz.from_env(@scope)).to_not be_nil
+      end
+    end
+  end
+
+  describe '#from_well_known_path' do
+    before(:example) do
+      @home = ENV['HOME']
+      @scope = 'https://www.googleapis.com/auth/userinfo.profile'
+      @known_path = CredentialsLoader::WELL_KNOWN_PATH
+      @clz = UserRefreshCredentials
+    end
+
+    after(:example) do
+      ENV['HOME'] = @home unless @home == ENV['HOME']
+    end
+
+    it 'is nil if no file exists' do
+      ENV['HOME'] = File.dirname(__FILE__)
+      expect(UserRefreshCredentials.from_well_known_path(@scope)).to be_nil
+    end
+
+    it 'fails if the file is invalid' do
+      needed = %w(client_id client_secret refresh_token)
+      needed.each do |missing|
+        Dir.mktmpdir do |dir|
+          key_path = File.join(dir, '.config', @known_path)
+          FileUtils.mkdir_p(File.dirname(key_path))
+          File.write(key_path, cred_json_text(missing))
+          ENV['HOME'] = dir
+          expect { @clz.from_env(@scope) }.to raise_error
+        end
+      end
+    end
+
+    it 'successfully loads the file when it is present' do
+      Dir.mktmpdir do |dir|
+        key_path = File.join(dir, '.config', @known_path)
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        ENV['HOME'] = dir
+        expect(@clz.from_well_known_path(@scope)).to_not be_nil
+      end
+    end
+  end
+end