github.com/grailbio/base@v0.0.11/errors/once_test.go (about)

     1  // Copyright 2018 GRAIL, Inc. All rights reserved.
     2  // Use of this source code is governed by the Apache-2.0
     3  // license that can be found in the LICENSE file.
     4  
     5  package errors_test
     6  
     7  import (
     8  	"fmt"
     9  	"runtime"
    10  	"testing"
    11  
    12  	"github.com/grailbio/base/errors"
    13  	"github.com/stretchr/testify/require"
    14  )
    15  
    16  func TestOnce(t *testing.T) {
    17  	e := errors.Once{}
    18  	require.NoError(t, e.Err())
    19  
    20  	e.Set(errors.New("testerror"))
    21  	require.EqualError(t, e.Err(), "testerror")
    22  	e.Set(errors.New("testerror2")) // ignored
    23  	require.EqualError(t, e.Err(), "testerror")
    24  	runtime.GC()
    25  	require.EqualError(t, e.Err(), "testerror")
    26  }
    27  
    28  func BenchmarkReadNoError(b *testing.B) {
    29  	e := errors.Once{}
    30  	for i := 0; i < b.N; i++ {
    31  		if e.Err() != nil {
    32  			require.Fail(b, "err")
    33  		}
    34  	}
    35  }
    36  
    37  func BenchmarkReadError(b *testing.B) {
    38  	e := errors.Once{}
    39  	e.Set(errors.New("testerror"))
    40  	for i := 0; i < b.N; i++ {
    41  		if e.Err() == nil {
    42  			require.Fail(b, "err")
    43  		}
    44  	}
    45  }
    46  
    47  func BenchmarkSet(b *testing.B) {
    48  	e := errors.Once{}
    49  	err := errors.New("testerror")
    50  	for i := 0; i < b.N; i++ {
    51  		e.Set(err)
    52  	}
    53  }
    54  
    55  func ExampleOnce() {
    56  	e := errors.Once{}
    57  	fmt.Printf("Error: %v\n", e.Err())
    58  	e.Set(errors.New("test error 0"))
    59  	fmt.Printf("Error: %v\n", e.Err())
    60  	e.Set(errors.New("test error 1"))
    61  	fmt.Printf("Error: %v\n", e.Err())
    62  	// Output:
    63  	// Error: <nil>
    64  	// Error: test error 0
    65  	// Error: test error 0
    66  }