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Source file src/bytes/compare_test.go

Documentation: bytes

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package bytes_test
     6  
     7  import (
     8  	. "bytes"
     9  	"testing"
    10  )
    11  
    12  var compareTests = []struct {
    13  	a, b []byte
    14  	i    int
    15  }{
    16  	{[]byte(""), []byte(""), 0},
    17  	{[]byte("a"), []byte(""), 1},
    18  	{[]byte(""), []byte("a"), -1},
    19  	{[]byte("abc"), []byte("abc"), 0},
    20  	{[]byte("abd"), []byte("abc"), 1},
    21  	{[]byte("abc"), []byte("abd"), -1},
    22  	{[]byte("ab"), []byte("abc"), -1},
    23  	{[]byte("abc"), []byte("ab"), 1},
    24  	{[]byte("x"), []byte("ab"), 1},
    25  	{[]byte("ab"), []byte("x"), -1},
    26  	{[]byte("x"), []byte("a"), 1},
    27  	{[]byte("b"), []byte("x"), -1},
    28  	// test runtime·memeq's chunked implementation
    29  	{[]byte("abcdefgh"), []byte("abcdefgh"), 0},
    30  	{[]byte("abcdefghi"), []byte("abcdefghi"), 0},
    31  	{[]byte("abcdefghi"), []byte("abcdefghj"), -1},
    32  	{[]byte("abcdefghj"), []byte("abcdefghi"), 1},
    33  	// nil tests
    34  	{nil, nil, 0},
    35  	{[]byte(""), nil, 0},
    36  	{nil, []byte(""), 0},
    37  	{[]byte("a"), nil, 1},
    38  	{nil, []byte("a"), -1},
    39  }
    40  
    41  func TestCompare(t *testing.T) {
    42  	for _, tt := range compareTests {
    43  		cmp := Compare(tt.a, tt.b)
    44  		if cmp != tt.i {
    45  			t.Errorf(`Compare(%q, %q) = %v`, tt.a, tt.b, cmp)
    46  		}
    47  	}
    48  }
    49  
    50  func TestCompareIdenticalSlice(t *testing.T) {
    51  	var b = []byte("Hello Gophers!")
    52  	if Compare(b, b) != 0 {
    53  		t.Error("b != b")
    54  	}
    55  	if Compare(b, b[:1]) != 1 {
    56  		t.Error("b > b[:1] failed")
    57  	}
    58  }
    59  
    60  func TestCompareBytes(t *testing.T) {
    61  	n := 128
    62  	a := make([]byte, n+1)
    63  	b := make([]byte, n+1)
    64  	for len := 0; len < 128; len++ {
    65  		// randomish but deterministic data. No 0 or 255.
    66  		for i := 0; i < len; i++ {
    67  			a[i] = byte(1 + 31*i%254)
    68  			b[i] = byte(1 + 31*i%254)
    69  		}
    70  		// data past the end is different
    71  		for i := len; i <= n; i++ {
    72  			a[i] = 8
    73  			b[i] = 9
    74  		}
    75  		cmp := Compare(a[:len], b[:len])
    76  		if cmp != 0 {
    77  			t.Errorf(`CompareIdentical(%d) = %d`, len, cmp)
    78  		}
    79  		if len > 0 {
    80  			cmp = Compare(a[:len-1], b[:len])
    81  			if cmp != -1 {
    82  				t.Errorf(`CompareAshorter(%d) = %d`, len, cmp)
    83  			}
    84  			cmp = Compare(a[:len], b[:len-1])
    85  			if cmp != 1 {
    86  				t.Errorf(`CompareBshorter(%d) = %d`, len, cmp)
    87  			}
    88  		}
    89  		for k := 0; k < len; k++ {
    90  			b[k] = a[k] - 1
    91  			cmp = Compare(a[:len], b[:len])
    92  			if cmp != 1 {
    93  				t.Errorf(`CompareAbigger(%d,%d) = %d`, len, k, cmp)
    94  			}
    95  			b[k] = a[k] + 1
    96  			cmp = Compare(a[:len], b[:len])
    97  			if cmp != -1 {
    98  				t.Errorf(`CompareBbigger(%d,%d) = %d`, len, k, cmp)
    99  			}
   100  			b[k] = a[k]
   101  		}
   102  	}
   103  }
   104  
   105  func BenchmarkCompareBytesEqual(b *testing.B) {
   106  	b1 := []byte("Hello Gophers!")
   107  	b2 := []byte("Hello Gophers!")
   108  	for i := 0; i < b.N; i++ {
   109  		if Compare(b1, b2) != 0 {
   110  			b.Fatal("b1 != b2")
   111  		}
   112  	}
   113  }
   114  
   115  func BenchmarkCompareBytesToNil(b *testing.B) {
   116  	b1 := []byte("Hello Gophers!")
   117  	var b2 []byte
   118  	for i := 0; i < b.N; i++ {
   119  		if Compare(b1, b2) != 1 {
   120  			b.Fatal("b1 > b2 failed")
   121  		}
   122  	}
   123  }
   124  
   125  func BenchmarkCompareBytesEmpty(b *testing.B) {
   126  	b1 := []byte("")
   127  	b2 := b1
   128  	for i := 0; i < b.N; i++ {
   129  		if Compare(b1, b2) != 0 {
   130  			b.Fatal("b1 != b2")
   131  		}
   132  	}
   133  }
   134  
   135  func BenchmarkCompareBytesIdentical(b *testing.B) {
   136  	b1 := []byte("Hello Gophers!")
   137  	b2 := b1
   138  	for i := 0; i < b.N; i++ {
   139  		if Compare(b1, b2) != 0 {
   140  			b.Fatal("b1 != b2")
   141  		}
   142  	}
   143  }
   144  
   145  func BenchmarkCompareBytesSameLength(b *testing.B) {
   146  	b1 := []byte("Hello Gophers!")
   147  	b2 := []byte("Hello, Gophers")
   148  	for i := 0; i < b.N; i++ {
   149  		if Compare(b1, b2) != -1 {
   150  			b.Fatal("b1 < b2 failed")
   151  		}
   152  	}
   153  }
   154  
   155  func BenchmarkCompareBytesDifferentLength(b *testing.B) {
   156  	b1 := []byte("Hello Gophers!")
   157  	b2 := []byte("Hello, Gophers!")
   158  	for i := 0; i < b.N; i++ {
   159  		if Compare(b1, b2) != -1 {
   160  			b.Fatal("b1 < b2 failed")
   161  		}
   162  	}
   163  }
   164  
   165  func BenchmarkCompareBytesBigUnaligned(b *testing.B) {
   166  	b.StopTimer()
   167  	b1 := make([]byte, 0, 1<<20)
   168  	for len(b1) < 1<<20 {
   169  		b1 = append(b1, "Hello Gophers!"...)
   170  	}
   171  	b2 := append([]byte("hello"), b1...)
   172  	b.StartTimer()
   173  	for i := 0; i < b.N; i++ {
   174  		if Compare(b1, b2[len("hello"):]) != 0 {
   175  			b.Fatal("b1 != b2")
   176  		}
   177  	}
   178  	b.SetBytes(int64(len(b1)))
   179  }
   180  
   181  func BenchmarkCompareBytesBig(b *testing.B) {
   182  	b.StopTimer()
   183  	b1 := make([]byte, 0, 1<<20)
   184  	for len(b1) < 1<<20 {
   185  		b1 = append(b1, "Hello Gophers!"...)
   186  	}
   187  	b2 := append([]byte{}, b1...)
   188  	b.StartTimer()
   189  	for i := 0; i < b.N; i++ {
   190  		if Compare(b1, b2) != 0 {
   191  			b.Fatal("b1 != b2")
   192  		}
   193  	}
   194  	b.SetBytes(int64(len(b1)))
   195  }
   196  
   197  func BenchmarkCompareBytesBigIdentical(b *testing.B) {
   198  	b.StopTimer()
   199  	b1 := make([]byte, 0, 1<<20)
   200  	for len(b1) < 1<<20 {
   201  		b1 = append(b1, "Hello Gophers!"...)
   202  	}
   203  	b2 := b1
   204  	b.StartTimer()
   205  	for i := 0; i < b.N; i++ {
   206  		if Compare(b1, b2) != 0 {
   207  			b.Fatal("b1 != b2")
   208  		}
   209  	}
   210  	b.SetBytes(int64(len(b1)))
   211  }
   212  

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