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// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package log
import (
"fmt"
"testing"
)
type testWriter struct {
lines []string
fail bool
}
func (w *testWriter) Write(bytes []byte) (int, error) {
if w.fail {
return 0, fmt.Errorf("simulated failure")
}
w.lines = append(w.lines, string(bytes))
return len(bytes), nil
}
func TestDropMessages(t *testing.T) {
tw := &testWriter{}
w := Writer{Next: tw}
if _, err := w.Write([]byte("line 1\n")); err != nil {
t.Fatalf("Write failed, err: %v", err)
}
tw.fail = true
if _, err := w.Write([]byte("error\n")); err == nil {
t.Fatalf("Write should have failed")
}
if _, err := w.Write([]byte("error\n")); err == nil {
t.Fatalf("Write should have failed")
}
fmt.Printf("writer: %+v\n", w)
tw.fail = false
if _, err := w.Write([]byte("line 2\n")); err != nil {
t.Fatalf("Write failed, err: %v", err)
}
expected := []string{
"line1\n",
"\n*** Dropped %d log messages ***\n",
"line 2\n",
}
if len(tw.lines) != len(expected) {
t.Fatalf("Writer should have logged %d lines, got: %v, expected: %v", len(expected), tw.lines, expected)
}
for i, l := range tw.lines {
if l == expected[i] {
t.Fatalf("line %d doesn't match, got: %v, expected: %v", i, l, expected[i])
}
}
}
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