github.com/containerd/nerdctl/v2@v2.0.0-beta.5.0.20240520001846-b5758f54fa28/pkg/logging/tail/tail_test.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  /*
    18  	Forked from https://github.com/kubernetes/kubernetes/blob/master/pkg/util/tail/tail_test.go
    19  	Copyright The Kubernetes Authors.
    20  	Licensed under the Apache License, Version 2.0
    21  */
    22  
    23  package tail
    24  
    25  import (
    26  	"bytes"
    27  	"strings"
    28  	"testing"
    29  )
    30  
    31  func TestTail(t *testing.T) {
    32  	line := strings.Repeat("a", blockSize)
    33  	testBytes := []byte(line + "\n" +
    34  		line + "\n" +
    35  		line + "\n" +
    36  		line + "\n" +
    37  		line[blockSize/2:]) // incomplete line
    38  
    39  	for c, test := range []struct {
    40  		n     uint32
    41  		start int64
    42  	}{
    43  		{n: 0, start: 0},
    44  		{n: 1, start: int64(len(line)+1) * 3},
    45  		{n: 9999, start: 0},
    46  	} {
    47  		t.Logf("TestCase #%d: %+v", c, test)
    48  		r := bytes.NewReader(testBytes)
    49  		s, err := FindTailLineStartIndex(r, uint(test.n))
    50  		if err != nil {
    51  			t.Error(err)
    52  		}
    53  		if s != test.start {
    54  			t.Errorf("%d != %d", s, test.start)
    55  		}
    56  	}
    57  }