github.com/brahmaroutu/docker@v1.2.1-0.20160809185609-eb28dde01f16/pkg/ioutils/multireader_test.go (about)

     1  package ioutils
     2  
     3  import (
     4  	"bytes"
     5  	"fmt"
     6  	"io"
     7  	"io/ioutil"
     8  	"os"
     9  	"strings"
    10  	"testing"
    11  )
    12  
    13  func TestMultiReadSeekerReadAll(t *testing.T) {
    14  	str := "hello world"
    15  	s1 := strings.NewReader(str + " 1")
    16  	s2 := strings.NewReader(str + " 2")
    17  	s3 := strings.NewReader(str + " 3")
    18  	mr := MultiReadSeeker(s1, s2, s3)
    19  
    20  	expectedSize := int64(s1.Len() + s2.Len() + s3.Len())
    21  
    22  	b, err := ioutil.ReadAll(mr)
    23  	if err != nil {
    24  		t.Fatal(err)
    25  	}
    26  
    27  	expected := "hello world 1hello world 2hello world 3"
    28  	if string(b) != expected {
    29  		t.Fatalf("ReadAll failed, got: %q, expected %q", string(b), expected)
    30  	}
    31  
    32  	size, err := mr.Seek(0, os.SEEK_END)
    33  	if err != nil {
    34  		t.Fatal(err)
    35  	}
    36  	if size != expectedSize {
    37  		t.Fatalf("reader size does not match, got %d, expected %d", size, expectedSize)
    38  	}
    39  
    40  	// Reset the position and read again
    41  	pos, err := mr.Seek(0, os.SEEK_SET)
    42  	if err != nil {
    43  		t.Fatal(err)
    44  	}
    45  	if pos != 0 {
    46  		t.Fatalf("expected position to be set to 0, got %d", pos)
    47  	}
    48  
    49  	b, err = ioutil.ReadAll(mr)
    50  	if err != nil {
    51  		t.Fatal(err)
    52  	}
    53  
    54  	if string(b) != expected {
    55  		t.Fatalf("ReadAll failed, got: %q, expected %q", string(b), expected)
    56  	}
    57  }
    58  
    59  func TestMultiReadSeekerReadEach(t *testing.T) {
    60  	str := "hello world"
    61  	s1 := strings.NewReader(str + " 1")
    62  	s2 := strings.NewReader(str + " 2")
    63  	s3 := strings.NewReader(str + " 3")
    64  	mr := MultiReadSeeker(s1, s2, s3)
    65  
    66  	var totalBytes int64
    67  	for i, s := range []*strings.Reader{s1, s2, s3} {
    68  		sLen := int64(s.Len())
    69  		buf := make([]byte, s.Len())
    70  		expected := []byte(fmt.Sprintf("%s %d", str, i+1))
    71  
    72  		if _, err := mr.Read(buf); err != nil && err != io.EOF {
    73  			t.Fatal(err)
    74  		}
    75  
    76  		if !bytes.Equal(buf, expected) {
    77  			t.Fatalf("expected %q to be %q", string(buf), string(expected))
    78  		}
    79  
    80  		pos, err := mr.Seek(0, os.SEEK_CUR)
    81  		if err != nil {
    82  			t.Fatalf("iteration: %d, error: %v", i+1, err)
    83  		}
    84  
    85  		// check that the total bytes read is the current position of the seeker
    86  		totalBytes += sLen
    87  		if pos != totalBytes {
    88  			t.Fatalf("expected current position to be: %d, got: %d, iteration: %d", totalBytes, pos, i+1)
    89  		}
    90  
    91  		// This tests not only that SEEK_SET and SEEK_CUR give the same values, but that the next iteration is in the expected position as well
    92  		newPos, err := mr.Seek(pos, os.SEEK_SET)
    93  		if err != nil {
    94  			t.Fatal(err)
    95  		}
    96  		if newPos != pos {
    97  			t.Fatalf("expected to get same position when calling SEEK_SET with value from SEEK_CUR, cur: %d, set: %d", pos, newPos)
    98  		}
    99  	}
   100  }
   101  
   102  func TestMultiReadSeekerReadSpanningChunks(t *testing.T) {
   103  	str := "hello world"
   104  	s1 := strings.NewReader(str + " 1")
   105  	s2 := strings.NewReader(str + " 2")
   106  	s3 := strings.NewReader(str + " 3")
   107  	mr := MultiReadSeeker(s1, s2, s3)
   108  
   109  	buf := make([]byte, s1.Len()+3)
   110  	_, err := mr.Read(buf)
   111  	if err != nil {
   112  		t.Fatal(err)
   113  	}
   114  
   115  	// expected is the contents of s1 + 3 bytes from s2, ie, the `hel` at the end of this string
   116  	expected := "hello world 1hel"
   117  	if string(buf) != expected {
   118  		t.Fatalf("expected %s to be %s", string(buf), expected)
   119  	}
   120  }
   121  
   122  func TestMultiReadSeekerNegativeSeek(t *testing.T) {
   123  	str := "hello world"
   124  	s1 := strings.NewReader(str + " 1")
   125  	s2 := strings.NewReader(str + " 2")
   126  	s3 := strings.NewReader(str + " 3")
   127  	mr := MultiReadSeeker(s1, s2, s3)
   128  
   129  	s1Len := s1.Len()
   130  	s2Len := s2.Len()
   131  	s3Len := s3.Len()
   132  
   133  	s, err := mr.Seek(int64(-1*s3.Len()), os.SEEK_END)
   134  	if err != nil {
   135  		t.Fatal(err)
   136  	}
   137  	if s != int64(s1Len+s2Len) {
   138  		t.Fatalf("expected %d to be %d", s, s1.Len()+s2.Len())
   139  	}
   140  
   141  	buf := make([]byte, s3Len)
   142  	if _, err := mr.Read(buf); err != nil && err != io.EOF {
   143  		t.Fatal(err)
   144  	}
   145  	expected := fmt.Sprintf("%s %d", str, 3)
   146  	if string(buf) != fmt.Sprintf("%s %d", str, 3) {
   147  		t.Fatalf("expected %q to be %q", string(buf), expected)
   148  	}
   149  }