diff --git a/activesupport/lib/active_support/testing/method_call_assertions.rb b/activesupport/lib/active_support/testing/method_call_assertions.rb
index ac584ff535..c8d2dbaa52 100644
--- a/activesupport/lib/active_support/testing/method_call_assertions.rb
+++ b/activesupport/lib/active_support/testing/method_call_assertions.rb
@@ -28,7 +28,7 @@ module ActiveSupport
 
           object.stub(method_name, mock, &block)
 
-          mock.verify
+          assert_mock(mock)
         end
 
         def assert_not_called(object, method_name, message = nil, &block)
diff --git a/activesupport/test/cache/stores/file_store_test.rb b/activesupport/test/cache/stores/file_store_test.rb
index 517a0648f6..49ebf836ba 100644
--- a/activesupport/test/cache/stores/file_store_test.rb
+++ b/activesupport/test/cache/stores/file_store_test.rb
@@ -47,7 +47,7 @@ class FileStoreTest < ActiveSupport::TestCase
 
   def test_clear_without_cache_dir
     FileUtils.rm_r(cache_dir)
-    @cache.clear
+    assert_nothing_raised { @cache.clear }
   end
 
   def test_long_uri_encoded_keys
diff --git a/activesupport/test/cache/stores/null_store_test.rb b/activesupport/test/cache/stores/null_store_test.rb
index 925ae00c86..984448ff66 100644
--- a/activesupport/test/cache/stores/null_store_test.rb
+++ b/activesupport/test/cache/stores/null_store_test.rb
@@ -10,11 +10,15 @@ class NullStoreTest < ActiveSupport::TestCase
   end
 
   def test_clear
+    @cache.write("name", "value")
     @cache.clear
+    assert_nil @cache.read("name")
   end
 
   def test_cleanup
+    @cache.write("name", "value")
     @cache.cleanup
+    assert_nil @cache.read("name")
   end
 
   def test_write
@@ -44,6 +48,7 @@ class NullStoreTest < ActiveSupport::TestCase
   def test_delete_matched
     @cache.write("name", "value")
     @cache.delete_matched(/name/)
+    assert_nil @cache.read("name")
   end
 
   def test_local_store_strategy
diff --git a/activesupport/test/core_ext/kernel_test.rb b/activesupport/test/core_ext/kernel_test.rb
index 505192ba1b..861a6def52 100644
--- a/activesupport/test/core_ext/kernel_test.rb
+++ b/activesupport/test/core_ext/kernel_test.rb
@@ -45,9 +45,11 @@ class KernelSuppressTest < ActiveSupport::TestCase
   end
 
   def test_suppression
-    suppress(ArgumentError) { raise ArgumentError }
-    suppress(LoadError) { raise LoadError }
-    suppress(LoadError, ArgumentError) { raise LoadError }
-    suppress(LoadError, ArgumentError) { raise ArgumentError }
+    assert_nothing_raised do
+      suppress(ArgumentError) { raise ArgumentError }
+      suppress(LoadError) { raise LoadError }
+      suppress(LoadError, ArgumentError) { raise LoadError }
+      suppress(LoadError, ArgumentError) { raise ArgumentError }
+    end
   end
 end
diff --git a/activesupport/test/deprecation_test.rb b/activesupport/test/deprecation_test.rb
index 3adab7b223..2523108997 100644
--- a/activesupport/test/deprecation_test.rb
+++ b/activesupport/test/deprecation_test.rb
@@ -508,8 +508,10 @@ class DeprecationTest < ActiveSupport::TestCase
   def test_no_disallowed_behavior_with_no_disallowed_messages
     resetting_disallowed_deprecation_config do
       ActiveSupport::Deprecation.disallowed_behavior = :raise
-      @dtc.none
-      @dtc.partially
+      assert_nothing_raised do
+        @dtc.none
+        @dtc.partially
+      end
     end
   end
 
@@ -518,7 +520,7 @@ class DeprecationTest < ActiveSupport::TestCase
       ActiveSupport::Deprecation.disallowed_behavior = :raise
       ActiveSupport::Deprecation.disallowed_warnings = ["foo=nil"]
 
-      @dtc.none
+      assert_nothing_raised { @dtc.none }
     end
   end
 
diff --git a/activesupport/test/log_subscriber_test.rb b/activesupport/test/log_subscriber_test.rb
index d4bd082def..0bf8e2a801 100644
--- a/activesupport/test/log_subscriber_test.rb
+++ b/activesupport/test/log_subscriber_test.rb
@@ -92,10 +92,11 @@ class SyncLogSubscriberTest < ActiveSupport::TestCase
   end
 
   def test_does_not_send_the_event_if_it_doesnt_match_the_class
-    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
-    instrument "unknown_event.my_log_subscriber"
-    wait
-    # If we get here, it means that NoMethodError was not raised.
+    assert_nothing_raised do
+      ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+      instrument "unknown_event.my_log_subscriber"
+      wait
+    end
   end
 
   def test_does_not_send_the_event_if_logger_is_nil
@@ -108,9 +109,11 @@ class SyncLogSubscriberTest < ActiveSupport::TestCase
   end
 
   def test_does_not_fail_with_non_namespaced_events
-    ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
-    instrument "whatever"
-    wait
+    assert_nothing_raised do
+      ActiveSupport::LogSubscriber.attach_to :my_log_subscriber, @log_subscriber
+      instrument "whatever"
+      wait
+    end
   end
 
   def test_flushes_loggers
diff --git a/activesupport/test/logger_test.rb b/activesupport/test/logger_test.rb
index 2461b48bc6..ff368d60e5 100644
--- a/activesupport/test/logger_test.rb
+++ b/activesupport/test/logger_test.rb
@@ -43,7 +43,9 @@ class LoggerTest < ActiveSupport::TestCase
     str = +"\x80"
     str.force_encoding("ASCII-8BIT")
 
-    logger.add Logger::DEBUG, str
+    assert_nothing_raised do
+      logger.add Logger::DEBUG, str
+    end
   ensure
     logger.close
     t.close true
@@ -61,7 +63,9 @@ class LoggerTest < ActiveSupport::TestCase
     str = +"\x80"
     str.force_encoding("ASCII-8BIT")
 
-    logger.add Logger::DEBUG, str
+    assert_nothing_raised do
+      logger.add Logger::DEBUG, str
+    end
   ensure
     logger.close
     File.unlink fname
diff --git a/activesupport/test/metadata/shared_metadata_tests.rb b/activesupport/test/metadata/shared_metadata_tests.rb
index cf571223e5..17435573c0 100644
--- a/activesupport/test/metadata/shared_metadata_tests.rb
+++ b/activesupport/test/metadata/shared_metadata_tests.rb
@@ -14,10 +14,10 @@ module SharedMessageMetadataTests
   end
 
   def test_verifies_array_when_purpose_matches
-    unless null_serializing?
-      data = [ "credit_card_no: 5012-6748-9087-5678", { "card_holder" => "Donald", "issued_on" => Time.local(2017) }, 12345 ]
-      assert_equal data, parse(generate(data, purpose: :registration), purpose: :registration)
-    end
+    skip if null_serializing?
+
+    data = [ "credit_card_no: 5012-6748-9087-5678", { "card_holder" => "Donald", "issued_on" => Time.local(2017) }, 12345 ]
+    assert_equal data, parse(generate(data, purpose: :registration), purpose: :registration)
   end
 
   def test_encryption_and_decryption_with_different_purposes_returns_nil
diff --git a/activesupport/test/notifications_test.rb b/activesupport/test/notifications_test.rb
index 7877967ee0..ea768915a5 100644
--- a/activesupport/test/notifications_test.rb
+++ b/activesupport/test/notifications_test.rb
@@ -185,8 +185,10 @@ module Notifications
 
       ActiveSupport::Notifications.subscribe("foo", TestSubscriber.new)
 
-      ActiveSupport::Notifications.instrument("foo") do
-        ActiveSupport::Notifications.subscribe("foo") { }
+      assert_nothing_raised do
+        ActiveSupport::Notifications.instrument("foo") do
+          ActiveSupport::Notifications.subscribe("foo") { }
+        end
       end
     ensure
       ActiveSupport::Notifications.notifier = old_notifier