You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: pipeline_test.go
    path of file: ./repos/trivy/pkg/parallel
    
    the code of the file until where you have to start completion: package parallel_test

import (
	"context"
	"fmt"
	"math"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/aquasecurity/trivy/pkg/parallel"
)

func TestPipeline_Do(t
    
func TestPipeline_Do(t *testing.T) {
	type field struct {
		numWorkers int
		items      []float64
		onItem     func(context.Context, float64) (float64, error)
	}
	type testCase struct {
		name    string
		field   field
		want    float64
		wantErr require.ErrorAssertionFunc
	}
	tests := []testCase{
		{
			name: "pow",
			field: field{
				numWorkers: 5,
				items: []float64{
					1,
					2,
					3,
					4,
					5,
					6,
					7,
					8,
					9,
					10,
				},
				onItem: func(_ context.Context, f float64) (float64, error) {
					return math.Pow(f, 2), nil
				},
			},
			want:    385,
			wantErr: require.NoError,
		},
		{
			name: "ceil",
			field: field{
				numWorkers: 3,
				items: []float64{
					1.1,
					2.2,
					3.3,
					4.4,
					5.5,
					-1.1,
					-2.2,
					-3.3,
				},
				onItem: func(_ context.Context, f float64) (float64, error) {
					return math.Round(f), nil
				},
			},
			want:    10,
			wantErr: require.NoError,
		},
		{
			name: "error in series",
			field: field{
				numWorkers: 1,
				items: []float64{
					1,
					2,
					3,
				},
				onItem: func(_ context.Context, f float64) (float64, error) {
					return 0, fmt.Errorf("error")
				},
			},
			wantErr: require.Error,
		},
		{
			name: "error in parallel",
			field: field{
				numWorkers: 3,
				items: []float64{
					1,
					2,
				},
				onItem: func(_ context.Context, f float64) (float64, error) {
					return 0, fmt.Errorf("error")
				},
			},
			wantErr: require.Error,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var got float64
			p := parallel.NewPipeline(tt.field.numWorkers, false, tt.field.items, tt.field.onItem, func(f float64) error {
				got += f
				return nil
			})
			err := p.Do(context.Background())
			tt.wantErr(t, err)
			assert.Equal(t, tt.want, got)
		})
	}
}