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: run_output_writer_test.go
    path of file: ./repos/beam/playground/backend/internal/streaming
    
    the code of the file until where you have to start completion: // Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License.  You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package streaming

import (
	"beam.apache.org/playground/backend/internal/cache"
	"beam.apache.org/playground/backend/internal/cache/local"
	"context"
	"github.com/google/uuid"
	"testing"
)

func TestRunOutputWriter_Write(t *testing.T) {
	pipelineId := uuid.New()
	cacheService := local.New(context.Background())
	err := cacheService.SetValue(context.Background(), pipelineId, cache.RunOutput, "MOCK_TEST_OUTPUT")
	if err != nil {
		panic(err)
	}

	type fields struct {
		Ctx          context.Context
		CacheService cache.Cache
		PipelineId   uuid.UUID
	}
	type args struct {
		p []byte
	}
	tests := []struct {
		name    string
		fields  fields
		args    args
		check   func() bool
		want    int
		wantErr bool
	}{
		{
			// Test case with calling Write method with empty string parameter.
			// As a result, want to receive 0.
			name: "empty string",
			fields: fields{
				Ctx:          context.Background(),
				CacheService: cacheService,
				PipelineId:   uuid.New(),
			},
			args: args{[]byte("")},
			check: func() bool {
				re
    
func TestRunOutputWriter_Write(t *testing.T) {
	pipelineId := uuid.New()
	cacheService := local.New(context.Background())
	err := cacheService.SetValue(context.Background(), pipelineId, cache.RunOutput, "MOCK_TEST_OUTPUT")
	if err != nil {
		panic(err)
	}

	type fields struct {
		Ctx          context.Context
		CacheService cache.Cache
		PipelineId   uuid.UUID
	}
	type args struct {
		p []byte
	}
	tests := []struct {
		name    string
		fields  fields
		args    args
		check   func() bool
		want    int
		wantErr bool
	}{
		{
			// Test case with calling Write method with empty string parameter.
			// As a result, want to receive 0.
			name: "empty string",
			fields: fields{
				Ctx:          context.Background(),
				CacheService: cacheService,
				PipelineId:   uuid.New(),
			},
			args: args{[]byte("")},
			check: func() bool {
				return true
			},
			want:    0,
			wantErr: false,
		},
		{
			// Test case with calling Write method with pipelineId which doesn't contain output yet.
			// As a result, want to receive an error.
			name: "output doesn't exist",
			fields: fields{
				Ctx:          context.Background(),
				CacheService: cacheService,
				PipelineId:   uuid.New(),
			},
			args: args{[]byte(" NEW_MOCK_OUTPUT")},
			check: func() bool {
				return true
			},
			want:    0,
			wantErr: true,
		},
		{
			// Test case with calling Write method with pipelineId which already contains output.
			// As a result, want to receive len of sent string.
			name: "output exists",
			fields: fields{
				Ctx:          context.Background(),
				CacheService: cacheService,
				PipelineId:   pipelineId,
			},
			args: args{[]byte(" NEW_MOCK_OUTPUT")},
			check: func() bool {
				value, err := cacheService.GetValue(context.Background(), pipelineId, cache.RunOutput)
				if err != nil {
					return false
				}
				return value == "MOCK_TEST_OUTPUT NEW_MOCK_OUTPUT"
			},
			want:    16,
			wantErr: false,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			row := &RunOutputWriter{
				Ctx:          tt.fields.Ctx,
				CacheService: tt.fields.CacheService,
				PipelineId:   tt.fields.PipelineId,
			}
			got, err := row.Write(tt.args.p)
			if (err != nil) != tt.wantErr {
				t.Errorf("Write() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if got != tt.want {
				t.Errorf("Write() got = %v, want %v", got, tt.want)
			}
			if !tt.check() {
				t.Errorf("Write() writes unexpectable data to cache")
			}
		})
	}
}