github.com/Prakhar-Agarwal-byte/moby@v0.0.0-20231027092010-a14e3e8ab87e/pkg/ioutils/readers_test.go (about)

     1  package ioutils // import "github.com/Prakhar-Agarwal-byte/moby/pkg/ioutils"
     2  
     3  import (
     4  	"context"
     5  	"errors"
     6  	"io"
     7  	"strings"
     8  	"testing"
     9  	"testing/iotest"
    10  	"time"
    11  )
    12  
    13  func TestReadCloserWrapperClose(t *testing.T) {
    14  	const text = "hello world"
    15  	testErr := errors.New("this will be called when closing")
    16  	wrapper := NewReadCloserWrapper(strings.NewReader(text), func() error {
    17  		return testErr
    18  	})
    19  
    20  	buf, err := io.ReadAll(wrapper)
    21  	if err != nil {
    22  		t.Errorf("io.ReadAll(wrapper) err = %v", err)
    23  	}
    24  	if string(buf) != text {
    25  		t.Errorf("expected %v, got: %v", text, string(buf))
    26  	}
    27  	err = wrapper.Close()
    28  	if !errors.Is(err, testErr) {
    29  		// readCloserWrapper should have called the anonymous func and thus, fail
    30  		t.Errorf("expected %v, got: %v", testErr, err)
    31  	}
    32  }
    33  
    34  func TestReaderErrWrapperReadOnError(t *testing.T) {
    35  	called := false
    36  	expectedErr := errors.New("error reader always fail")
    37  	wrapper := NewReaderErrWrapper(iotest.ErrReader(expectedErr), func() {
    38  		called = true
    39  	})
    40  	_, err := wrapper.Read([]byte{})
    41  	if !errors.Is(err, expectedErr) {
    42  		t.Errorf("expected %v, got: %v", expectedErr, err)
    43  	}
    44  	if !called {
    45  		t.Fatalf("readErrWrapper should have called the anonymous function on failure")
    46  	}
    47  }
    48  
    49  func TestReaderErrWrapperRead(t *testing.T) {
    50  	const text = "hello world"
    51  	wrapper := NewReaderErrWrapper(strings.NewReader(text), func() {
    52  		t.Fatalf("readErrWrapper should not have called the anonymous function")
    53  	})
    54  	num, err := wrapper.Read(make([]byte, len(text)+10))
    55  	if err != nil {
    56  		t.Error(err)
    57  	}
    58  	if expected := len(text); num != expected {
    59  		t.Errorf("readerErrWrapper should have read %d byte, but read %d", expected, num)
    60  	}
    61  }
    62  
    63  type perpetualReader struct{}
    64  
    65  func (p *perpetualReader) Read(buf []byte) (n int, err error) {
    66  	for i := 0; i != len(buf); i++ {
    67  		buf[i] = 'a'
    68  	}
    69  	return len(buf), nil
    70  }
    71  
    72  func TestCancelReadCloser(t *testing.T) {
    73  	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
    74  	defer cancel()
    75  	crc := NewCancelReadCloser(ctx, io.NopCloser(&perpetualReader{}))
    76  	for {
    77  		var buf [128]byte
    78  		_, err := crc.Read(buf[:])
    79  		if err == context.DeadlineExceeded {
    80  			break
    81  		} else if err != nil {
    82  			t.Fatalf("got unexpected error: %v", err)
    83  		}
    84  	}
    85  }