feat(test): add Stubs#clear to remove all stubs

docs/adapters/test-adapter.md

@@ -100,9 +100,16 @@ verify the order or count of any stub.
 stubs.verify_stubbed_calls
 ```
 
-After the test case is completed (possibly in an `after` hook), you should clear
-the default connection to prevent it from being cached between different tests.
-This allows for each test to have its own set of stubs
+After the test case is completed (possibly in an `after` hook), you should reset
+the stubs so each test starts with its own set. When you hold a reference to the
+`Stubs` instance, call `clear` to remove every stub, including consumed ones.
+
+```ruby
+stubs.clear
+```
+
+Alternatively, if you rely on the default connection, you can clear it to prevent
+it from being cached between different tests.
 
 ```ruby
 Faraday.default_connection = nil

lib/faraday/adapter/test.rb

@@ -127,6 +127,14 @@ def options(path, headers = {}, &block)
           new_stub(:options, path, headers, &block)
         end
 
+        # Removes all stubs, including the ones that have already been consumed.
+        def clear
+          @stubs_mutex.synchronize do
+            @stack.clear
+            @consumed.clear
+          end
+        end
+
         # Raises an error if any of the stubbed calls have not been made.
         def verify_stubbed_calls
           failed_stubs = []

spec/faraday/adapter/test_spec.rb

@@ -439,4 +439,22 @@ def make_request
       end
     end
   end
+
+  describe '#clear' do
+    it 'removes pending stubs' do
+      stubs.clear
+      expect { connection.get('/hello') }.to raise_error(described_class::Stubs::NotFound)
+    end
+
+    it 'removes already consumed stubs' do
+      expect(connection.get('/hello').body).to eq('hello')
+      stubs.clear
+      expect { connection.get('/hello') }.to raise_error(described_class::Stubs::NotFound)
+    end
+
+    it 'leaves the stubs empty' do
+      stubs.clear
+      expect(stubs).to be_empty
+    end
+  end
 end