diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2c7b94f2..4c9117e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 ### Enhancements
+- Add `:viewtag` for Espresso driver [appium-espresso-driver#189](https://github.com/appium/appium-espresso-driver/pull/189)
 
 ### Bug fixes
 
diff --git a/lib/appium_lib_core/common/base/search_context.rb b/lib/appium_lib_core/common/base/search_context.rb
index 02042d6d..a83940bc 100644
--- a/lib/appium_lib_core/common/base/search_context.rb
+++ b/lib/appium_lib_core/common/base/search_context.rb
@@ -5,18 +5,19 @@ module SearchContext
         # referenced: ::Selenium::WebDriver::SearchContext
 
         FINDERS = ::Selenium::WebDriver::SearchContext::FINDERS.merge(
-          accessibility_id: 'accessibility id',
-          image: '-image',
+          accessibility_id:     'accessibility id',
+          image:                '-image',
           # Android
-          uiautomator: '-android uiautomator',
+          uiautomator:          '-android uiautomator', # Unavailable in Espresso
+          viewtag:              '-android viewtag',     # Available in Espresso
           # iOS
-          uiautomation: '-ios uiautomation',
-          predicate: '-ios predicate string',
-          class_chain: '-ios class chain',
+          uiautomation:         '-ios uiautomation',
+          predicate:            '-ios predicate string',
+          class_chain:          '-ios class chain',
           # Windows
           windows_uiautomation: '-windows uiautomation',
           # Tizen
-          tizen_uiautomation: '-tizen uiautomation'
+          tizen_uiautomation:   '-tizen uiautomation'
         )
 
         #
@@ -54,6 +55,9 @@ module SearchContext
         #     # For Android
         #     ## With uiautomator
         #     find_elements :uiautomator, 'new UiSelector().clickable(true)'
+        #     ## With viewtag, but only for Espresso
+        #     ## `setTag`/`getTag` in https://developer.android.com/reference/android/view/View
+        #     find_elements :viewtag, 'new UiSelector().clickable(true)'
         #
         #     # For iOS
         #     ## With :predicate
@@ -113,7 +117,7 @@ def find_elements(*args)
 
         def _set_by_from_finders(how)
           by = FINDERS[how.to_sym]
-          raise ArgumentError, "cannot find element by #{how.inspect}" unless by
+          raise ArgumentError, "cannot find element by #{how.inspect}. Available finders are #{FINDERS.keys}." unless by
           by
         end
 
diff --git a/test/unit/driver_test.rb b/test/unit/driver_test.rb
index 04ff011a..4b4c4675 100644
--- a/test/unit/driver_test.rb
+++ b/test/unit/driver_test.rb
@@ -82,27 +82,25 @@ def test_default_timeout_for_http_client
     end
 
     def test_search_context_in_element_class
-      assert_equal 'class name', ::Selenium::WebDriver::Element::FINDERS[:class]
-      assert_equal 'class name', ::Selenium::WebDriver::Element::FINDERS[:class_name]
-      assert_equal 'css selector', ::Selenium::WebDriver::Element::FINDERS[:css]
-      assert_equal 'id', ::Selenium::WebDriver::Element::FINDERS[:id]
-      assert_equal 'link text', ::Selenium::WebDriver::Element::FINDERS[:link]
-      assert_equal 'link text', ::Selenium::WebDriver::Element::FINDERS[:link_text]
-      assert_equal 'name', ::Selenium::WebDriver::Element::FINDERS[:name]
-      assert_equal 'partial link text', ::Selenium::WebDriver::Element::FINDERS[:partial_link_text]
-      assert_equal 'tag name', ::Selenium::WebDriver::Element::FINDERS[:tag_name]
-      assert_equal 'xpath', ::Selenium::WebDriver::Element::FINDERS[:xpath]
-      assert_equal 'accessibility id', ::Selenium::WebDriver::Element::FINDERS[:accessibility_id]
-      assert_equal '-android uiautomator', ::Selenium::WebDriver::Element::FINDERS[:uiautomator]
-      assert_equal '-ios uiautomation', ::Selenium::WebDriver::Element::FINDERS[:uiautomation]
-      assert_equal '-ios predicate string', ::Selenium::WebDriver::Element::FINDERS[:predicate]
-      assert_equal '-ios class chain', ::Selenium::WebDriver::Element::FINDERS[:class_chain]
-      assert_equal '-ios uiautomation', ::Selenium::WebDriver::Element::FINDERS[:uiautomation]
-      assert_equal '-ios predicate string', ::Selenium::WebDriver::Element::FINDERS[:predicate]
-      assert_equal '-ios class chain', ::Selenium::WebDriver::Element::FINDERS[:class_chain]
-      assert_equal '-windows uiautomation', ::Selenium::WebDriver::Element::FINDERS[:windows_uiautomation]
-      assert_equal '-tizen uiautomation', ::Selenium::WebDriver::Element::FINDERS[:tizen_uiautomation]
-      assert_equal '-image', ::Selenium::WebDriver::Element::FINDERS[:image]
+      assert_equal 19, ::Selenium::WebDriver::Element::FINDERS.length
+      assert_equal({ class: 'class name',
+                     class_name: 'class name',
+                     css: 'css selector',
+                     id: 'id',
+                     link: 'link text',
+                     link_text: 'link text',
+                     name: 'name',
+                     partial_link_text: 'partial link text',
+                     tag_name: 'tag name',
+                     xpath: 'xpath',
+                     accessibility_id: 'accessibility id',
+                     image: '-image',
+                     uiautomator: '-android uiautomator',
+                     viewtag: '-android viewtag', uiautomation: '-ios uiautomation',
+                     predicate: '-ios predicate string',
+                     class_chain: '-ios class chain',
+                     windows_uiautomation: '-windows uiautomation',
+                     tizen_uiautomation: '-tizen uiautomation' }, ::Selenium::WebDriver::Element::FINDERS)
     end
   end
 end