diff --git a/internal/internal_workflow_testsuite.go b/internal/internal_workflow_testsuite.go
index 1b5bd1495..21dbab413 100644
--- a/internal/internal_workflow_testsuite.go
+++ b/internal/internal_workflow_testsuite.go
@@ -362,7 +362,6 @@ func (env *testWorkflowEnvironmentImpl) newTestWorkflowEnvironmentForChild(param
 	childEnv.startedHandler = startedHandler
 	childEnv.testWorkflowEnvironmentShared = env.testWorkflowEnvironmentShared
 	childEnv.workerOptions = env.workerOptions
-	childEnv.workflowInterceptors = env.workflowInterceptors
 	childEnv.workerOptions.DataConverter = params.dataConverter
 	childEnv.workflowInterceptors = env.workflowInterceptors
 	childEnv.registry = env.registry
diff --git a/internal/workflow_testsuite.go b/internal/workflow_testsuite.go
index 9796a4a9e..19e5ae3ee 100644
--- a/internal/workflow_testsuite.go
+++ b/internal/workflow_testsuite.go
@@ -240,8 +240,8 @@ func (t *TestWorkflowEnvironment) OnActivity(activity interface{}, args ...inter
 			panic(err)
 		}
 		fnName := getActivityFunctionName(t.impl.registry, activity)
-		t.impl.registry.RegisterActivityWithOptions(activity, RegisterActivityOptions{DisableAlreadyRegisteredCheck: true})
 		call = t.Mock.On(fnName, args...)
+
 	case reflect.String:
 		call = t.Mock.On(activity.(string), args...)
 	default:
@@ -289,12 +289,11 @@ func (t *TestWorkflowEnvironment) OnWorkflow(workflow interface{}, args ...inter
 		if alias, ok := t.impl.registry.getWorkflowAlias(fnName); ok {
 			fnName = alias
 		}
-		t.impl.registry.RegisterWorkflowWithOptions(workflow, RegisterWorkflowOptions{DisableAlreadyRegisteredCheck: true})
 		call = t.Mock.On(fnName, args...)
 	case reflect.String:
 		call = t.Mock.On(workflow.(string), args...)
 	default:
-		panic("workflow must be function or string")
+		panic("activity must be function or string")
 	}
 
 	return t.wrapCall(call)
diff --git a/internal/workflow_testsuite_test.go b/internal/workflow_testsuite_test.go
index c9a16d53c..ca1123247 100644
--- a/internal/workflow_testsuite_test.go
+++ b/internal/workflow_testsuite_test.go
@@ -23,8 +23,6 @@ package internal
 
 import (
 	"context"
-	"github.com/stretchr/testify/mock"
-	"github.com/stretchr/testify/suite"
 	"strings"
 	"testing"
 	"time"
@@ -129,120 +127,3 @@ func TestWorkflowReturnNil(t *testing.T) {
 	err := env.GetWorkflowResult(&r)
 	require.NoError(t, err)
 }
-
-func HelloWorkflow(ctx Context, name string) (string, error) {
-	ctx = WithActivityOptions(ctx, ActivityOptions{
-		ScheduleToCloseTimeout: time.Hour,
-		StartToCloseTimeout:    time.Hour,
-		ScheduleToStartTimeout: time.Hour,
-	})
-	var result string
-	err := ExecuteActivity(ctx, HelloActivity, name).Get(ctx, &result)
-	return result, err
-}
-
-func HelloActivity(ctx context.Context, name string) (string, error) {
-	return "Hello " + name + "!", nil
-}
-
-func TestWorkflowMockingWithoutRegistration(t *testing.T) {
-	testSuite := &WorkflowTestSuite{}
-	env := testSuite.NewTestWorkflowEnvironment()
-	env.OnWorkflow(HelloWorkflow, mock.Anything, mock.Anything).Return(
-		func(ctx Context, person string) (string, error) {
-			return "Hello " + person + "!", nil
-		})
-	// Workflow is mocked, no activity registration required
-	env.ExecuteWorkflow(HelloWorkflow, "Cadence")
-	require.NoError(t, env.GetWorkflowError())
-	var result string
-	err := env.GetWorkflowResult(&result)
-	require.NoError(t, err)
-	require.Equal(t, "Hello Cadence!", result)
-}
-
-func TestActivityMockingWithoutRegistration(t *testing.T) {
-	testSuite := &WorkflowTestSuite{}
-	env := testSuite.NewTestWorkflowEnvironment()
-	env.OnActivity(HelloActivity, mock.Anything, mock.Anything).Return(
-		func(ctx context.Context, person string) (string, error) {
-			return "Goodbye " + person + "!", nil
-		})
-	// Registration of activity not required
-	env.RegisterWorkflow(HelloWorkflow)
-	env.ExecuteWorkflow(HelloWorkflow, "Cadence")
-	require.NoError(t, env.GetWorkflowError())
-	var result string
-	err := env.GetWorkflowResult(&result)
-	require.NoError(t, err)
-	require.Equal(t, "Goodbye Cadence!", result)
-  
-type InterceptorTestSuite struct {
-	suite.Suite
-	WorkflowTestSuite
-
-	env         *TestWorkflowEnvironment
-	testFactory InterceptorFactory
-}
-
-type InterceptorFactory struct {
-	workflowInterceptorInvocationCounter      int
-	childWorkflowInterceptorInvocationCounter int
-}
-
-type Interceptor struct {
-	WorkflowInterceptorBase
-	workflowInterceptorInvocationCounter      *int
-	childWorkflowInterceptorInvocationCounter *int
-}
-
-func (i *Interceptor) ExecuteWorkflow(ctx Context, workflowType string, args ...interface{}) []interface{} {
-	*i.workflowInterceptorInvocationCounter += 1
-	return i.Next.ExecuteWorkflow(ctx, workflowType, args...)
-}
-func (i *Interceptor) ExecuteChildWorkflow(ctx Context, workflowType string, args ...interface{}) ChildWorkflowFuture {
-	*i.childWorkflowInterceptorInvocationCounter += 1
-	return i.Next.ExecuteChildWorkflow(ctx, workflowType, args...)
-}
-
-func (f *InterceptorFactory) NewInterceptor(_ *WorkflowInfo, next WorkflowInterceptor) WorkflowInterceptor {
-	return &Interceptor{
-		WorkflowInterceptorBase: WorkflowInterceptorBase{
-			Next: next,
-		},
-		workflowInterceptorInvocationCounter:      &f.workflowInterceptorInvocationCounter,
-		childWorkflowInterceptorInvocationCounter: &f.childWorkflowInterceptorInvocationCounter,
-	}
-}
-
-func (s *InterceptorTestSuite) SetupTest() {
-	// Create a test workflow environment with the trace interceptor configured.
-	s.env = s.NewTestWorkflowEnvironment()
-	s.testFactory = InterceptorFactory{}
-	s.env.SetWorkerOptions(WorkerOptions{
-		WorkflowInterceptorChainFactories: []WorkflowInterceptorFactory{
-			&s.testFactory,
-		},
-	})
-}
-
-func TestInterceptorTestSuite(t *testing.T) {
-	suite.Run(t, new(InterceptorTestSuite))
-}
-
-func (s *InterceptorTestSuite) Test_GeneralInterceptor_IsExecutedOnChildren() {
-	r := s.Require()
-	childWf := func(ctx Context) error {
-		return nil
-	}
-	s.env.RegisterWorkflowWithOptions(childWf, RegisterWorkflowOptions{Name: "child"})
-	wf := func(ctx Context) error {
-		return ExecuteChildWorkflow(ctx, childWf).Get(ctx, nil)
-	}
-	s.env.RegisterWorkflowWithOptions(wf, RegisterWorkflowOptions{Name: "parent"})
-	s.env.ExecuteWorkflow(wf)
-	r.True(s.env.IsWorkflowCompleted())
-	r.NoError(s.env.GetWorkflowError())
-	r.Equal(s.testFactory.workflowInterceptorInvocationCounter, 2)
-	r.Equal(s.testFactory.childWorkflowInterceptorInvocationCounter, 1)
-}