diff --git a/internal/internal_task_handlers_test.go b/internal/internal_task_handlers_test.go
index 63b813ed9..07da0ccb7 100644
--- a/internal/internal_task_handlers_test.go
+++ b/internal/internal_task_handlers_test.go
@@ -1897,3 +1897,189 @@ func Test_IsSearchAttributesMatched(t *testing.T) {
 		})
 	}
 }
+
+func Test__GetWorkflowStartedEvent(t *testing.T) {
+	wfStartedEvent := createTestEventWorkflowExecutionStarted(1, &s.WorkflowExecutionStartedEventAttributes{TaskList: &s.TaskList{Name: common.StringPtr("tl1")}})
+	h := &history{workflowTask: &workflowTask{task: &s.PollForDecisionTaskResponse{History: &s.History{Events: []*s.HistoryEvent{wfStartedEvent}}}}}
+	result, err := h.GetWorkflowStartedEvent()
+	require.NoError(t, err)
+	require.Equal(t, wfStartedEvent, result)
+
+	emptyHistory := &history{workflowTask: &workflowTask{task: &s.PollForDecisionTaskResponse{History: &s.History{}}}}
+	result, err = emptyHistory.GetWorkflowStartedEvent()
+	require.ErrorContains(t, err, "unable to find WorkflowExecutionStartedEventAttributes")
+	require.Nil(t, result)
+}
+
+func Test__verifyAllEventsProcessed(t *testing.T) {
+	testCases := []struct {
+		name        string
+		lastEventID int64
+		nextEventID int64
+		Message     string
+	}{
+		{
+			name:        "error",
+			lastEventID: 1,
+			nextEventID: 1,
+			Message:     "history_events: premature end of stream",
+		},
+		{
+			name:        "warn",
+			lastEventID: 1,
+			nextEventID: 3,
+			Message:     "history_events: processed events past the expected lastEventID",
+		},
+		{
+			name:        "success",
+			lastEventID: 1,
+			nextEventID: 2,
+		},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			obs, logs := observer.New(zap.WarnLevel)
+			logger := zap.New(obs)
+			h := &history{
+				lastEventID:   testCase.lastEventID,
+				nextEventID:   testCase.nextEventID,
+				eventsHandler: &workflowExecutionEventHandlerImpl{workflowEnvironmentImpl: &workflowEnvironmentImpl{logger: logger}}}
+			err := h.verifyAllEventsProcessed()
+			if testCase.name == "error" {
+				require.ErrorContains(t, err, testCase.Message)
+			} else if testCase.name == "warn" {
+				warnLogs := logs.FilterMessage(testCase.Message)
+				require.Len(t, warnLogs.All(), 1)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+
+}
+
+func Test__workflowCategorizedByTimeout(t *testing.T) {
+	testCases := []struct {
+		timeout          int32
+		expectedCategory string
+	}{
+		{
+			timeout:          1,
+			expectedCategory: "instant",
+		},
+		{
+			timeout:          1000,
+			expectedCategory: "short",
+		},
+		{
+			timeout:          2000,
+			expectedCategory: "intermediate",
+		},
+		{
+			timeout:          30000,
+			expectedCategory: "long",
+		},
+	}
+	for _, tt := range testCases {
+		t.Run(tt.expectedCategory, func(t *testing.T) {
+			wfContext := &workflowExecutionContextImpl{workflowInfo: &WorkflowInfo{ExecutionStartToCloseTimeoutSeconds: tt.timeout}}
+			require.Equal(t, tt.expectedCategory, workflowCategorizedByTimeout(wfContext))
+		})
+	}
+}
+
+func Test__SignalWorkflow(t *testing.T) {
+	mockCtrl := gomock.NewController(t)
+	mockService := workflowservicetest.NewMockClient(mockCtrl)
+	mockService.EXPECT().SignalWorkflowExecution(gomock.Any(), gomock.Any(), callOptions()...).Return(nil)
+	cadenceInvoker := &cadenceInvoker{
+		identity:  "Test_Cadence_Invoker",
+		service:   mockService,
+		taskToken: nil,
+	}
+	err := cadenceInvoker.SignalWorkflow(context.Background(), "test-domain", "test-workflow-id", "test-run-id", "test-signal-name", nil)
+	require.NoError(t, err)
+}
+
+func Test__getRetryBackoffWithNowTime(t *testing.T) {
+	now := time.Now()
+	testCases := []struct {
+		name            string
+		maxAttempts     int32
+		ExpInterval     time.Duration
+		result          time.Duration
+		attempt         int32
+		errReason       string
+		expireTime      time.Time
+		initialInterval time.Duration
+		maxInterval     time.Duration
+	}{
+		{
+			name:        "no max attempts or expiration interval set",
+			maxAttempts: 0,
+			ExpInterval: 0,
+			result:      noRetryBackoff,
+		},
+		{
+			name:        "max attempts done",
+			maxAttempts: 5,
+			attempt:     5,
+			result:      noRetryBackoff,
+		},
+		{
+			name:            "non retryable error",
+			maxAttempts:     5,
+			attempt:         2,
+			errReason:       "bad request",
+			initialInterval: time.Minute,
+			maxInterval:     time.Minute,
+			result:          noRetryBackoff,
+		},
+		{
+			name:            "fallback to max interval when calculated backoff is 0",
+			maxAttempts:     5,
+			attempt:         2,
+			initialInterval: 0,
+			maxInterval:     time.Minute,
+			result:          time.Minute,
+		},
+		{
+			name:            "fallback to no retry backoff when calculated backoff is 0 and max interval is not set",
+			maxAttempts:     5,
+			attempt:         2,
+			initialInterval: 0,
+			result:          noRetryBackoff,
+		},
+		{
+			name:            "expiry time reached",
+			maxAttempts:     5,
+			attempt:         2,
+			expireTime:      now.Add(time.Second),
+			initialInterval: time.Minute,
+			maxInterval:     time.Minute,
+			result:          noRetryBackoff,
+		},
+		{
+			name:            "retry after backoff",
+			maxAttempts:     5,
+			attempt:         2,
+			errReason:       "timeout",
+			initialInterval: time.Minute,
+			maxInterval:     time.Minute,
+			result:          time.Minute,
+		},
+	}
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+			policy := &RetryPolicy{
+				MaximumAttempts:          tt.maxAttempts,
+				ExpirationInterval:       tt.ExpInterval,
+				BackoffCoefficient:       2,
+				NonRetriableErrorReasons: []string{"bad request"},
+				MaximumInterval:          tt.maxInterval,
+				InitialInterval:          tt.initialInterval,
+			}
+			require.Equal(t, tt.result, getRetryBackoffWithNowTime(policy, tt.attempt, tt.errReason, now, tt.expireTime))
+		})
+	}
+}