diff --git a/spec/googleauth/get_application_default_spec.rb b/spec/googleauth/get_application_default_spec.rb
index 981a31b..05128c0 100644
--- a/spec/googleauth/get_application_default_spec.rb
+++ b/spec/googleauth/get_application_default_spec.rb
@@ -144,13 +144,11 @@ describe '#get_application_default' do
     it 'succeeds with system default file' do
       ENV.delete(@var_name) unless ENV[@var_name].nil?
       FakeFS do
-        Dir.mktmpdir do |dir|
-          key_path = File.join('/etc/google/auth/', CREDENTIALS_FILE_NAME)
-          FileUtils.mkdir_p(File.dirname(key_path))
-          File.write(key_path, cred_json_text)
-          expect(Google::Auth.get_application_default(@scope)).to_not be_nil
-          File.delete(key_path)
-        end
+        key_path = File.join('/etc/google/auth/', CREDENTIALS_FILE_NAME)
+        FileUtils.mkdir_p(File.dirname(key_path))
+        File.write(key_path, cred_json_text)
+        expect(Google::Auth.get_application_default(@scope)).to_not be_nil
+        File.delete(key_path)
       end
     end
 
diff --git a/spec/googleauth/service_account_spec.rb b/spec/googleauth/service_account_spec.rb
index 2938f0f..24f597b 100644
--- a/spec/googleauth/service_account_spec.rb
+++ b/spec/googleauth/service_account_spec.rb
@@ -242,19 +242,17 @@ describe Google::Auth::ServiceAccountCredentials do
 
     it 'is nil if no file exists' do
       FakeFS do
-        expect(ServiceAccountCredentials.from_system_default_path(@scope)).
-          to be_nil
+        expect(ServiceAccountCredentials.from_system_default_path(@scope))
+          .to be_nil
       end
     end
 
     it 'successfully loads the file when it is present' do
       FakeFS do
-        Dir.mktmpdir do |dir|
-          FileUtils.mkdir_p(File.dirname(@path))
-          File.write(@path, cred_json_text)
-          expect(@clz.from_system_default_path(@scope)).to_not be_nil
-          File.delete(@path)
-        end
+        FileUtils.mkdir_p(File.dirname(@path))
+        File.write(@path, cred_json_text)
+        expect(@clz.from_system_default_path(@scope)).to_not be_nil
+        File.delete(@path)
       end
     end
   end
diff --git a/spec/googleauth/user_refresh_spec.rb b/spec/googleauth/user_refresh_spec.rb
index 4462a6e..394edbd 100644
--- a/spec/googleauth/user_refresh_spec.rb
+++ b/spec/googleauth/user_refresh_spec.rb
@@ -196,8 +196,8 @@ describe Google::Auth::UserRefreshCredentials do
 
     it 'is nil if no file exists' do
       FakeFS do
-        expect(UserRefreshCredentials.from_system_default_path(@scope)).
-          to be_nil
+        expect(UserRefreshCredentials.from_system_default_path(@scope))
+          .to be_nil
       end
     end
 
@@ -205,25 +205,21 @@ describe Google::Auth::UserRefreshCredentials do
       needed = %w(client_id client_secret refresh_token)
       needed.each do |missing|
         FakeFS do
-          Dir.mktmpdir do |dir|
-            FileUtils.mkdir_p(File.dirname(@path))
-            File.write(@path, cred_json_text(missing))
-            expect { @clz.from_system_default_path(@scope) }.
-              to raise_error RuntimeError
-            File.delete(@path)
-          end
+          FileUtils.mkdir_p(File.dirname(@path))
+          File.write(@path, cred_json_text(missing))
+          expect { @clz.from_system_default_path(@scope) }
+            .to raise_error RuntimeError
+          File.delete(@path)
         end
       end
     end
 
     it 'successfully loads the file when it is present' do
       FakeFS do
-        Dir.mktmpdir do |dir|
-          FileUtils.mkdir_p(File.dirname(@path))
-          File.write(@path, cred_json_text)
-          expect(@clz.from_system_default_path(@scope)).to_not be_nil
-          File.delete(@path)
-        end
+        FileUtils.mkdir_p(File.dirname(@path))
+        File.write(@path, cred_json_text)
+        expect(@clz.from_system_default_path(@scope)).to_not be_nil
+        File.delete(@path)
       end
     end
   end