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Add responsive writers which adjust to terminal sizes
This commit is contained in:
Fabiano Franz
parent
8438089e96
commit
6d6aeb0027
124
pkg/util/term/term_writer.go
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124
pkg/util/term/term_writer.go
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package term
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import (
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"io"
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"os"
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"github.com/docker/docker/pkg/term"
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wordwrap "github.com/mitchellh/go-wordwrap"
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)
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type wordWrapWriter struct {
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limit uint
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writer io.Writer
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}
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// NewResponsiveWriter creates a Writer that detects the column width of the
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// terminal we are in, and adjusts every line width to fit and use recommended
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// terminal sizes for better readability. Does proper word wrapping automatically.
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// if terminal width >= 120 columns use 120 columns
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// if terminal width >= 100 columns use 100 columns
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// if terminal width >= 80 columns use 80 columns
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// In case we're not in a terminal or if it's smaller than 80 columns width,
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// doesn't do any wrapping.
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func NewResponsiveWriter(w io.Writer) io.Writer {
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file, ok := w.(*os.File)
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if !ok {
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return w
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}
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fd := file.Fd()
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if !term.IsTerminal(fd) {
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return w
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}
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terminalSize := GetSize(fd)
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if terminalSize == nil {
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return w
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}
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var limit uint
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switch {
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case terminalSize.Width >= 120:
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limit = 120
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case terminalSize.Width >= 100:
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limit = 100
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case terminalSize.Width >= 80:
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limit = 80
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}
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return NewWordWrapWriter(w, limit)
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}
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// NewWordWrapWriter is a Writer that supports a limit of characters on every line
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// and does auto word wrapping that respects that limit.
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func NewWordWrapWriter(w io.Writer, limit uint) io.Writer {
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return &wordWrapWriter{
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limit: limit,
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writer: w,
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}
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}
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func (w wordWrapWriter) Write(p []byte) (nn int, err error) {
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if w.limit == 0 {
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return w.writer.Write(p)
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}
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original := string(p)
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wrapped := wordwrap.WrapString(original, w.limit)
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return w.writer.Write([]byte(wrapped))
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}
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// NewPunchCardWriter is a NewWordWrapWriter that limits the line width to 80 columns.
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func NewPunchCardWriter(w io.Writer) io.Writer {
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return NewWordWrapWriter(w, 80)
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}
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type maxWidthWriter struct {
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maxWidth uint
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currentWidth uint
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written uint
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writer io.Writer
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}
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// NewMaxWidthWriter is a Writer that supports a limit of characters on every
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// line, but doesn't do any word wrapping automatically.
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func NewMaxWidthWriter(w io.Writer, maxWidth uint) io.Writer {
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return &maxWidthWriter{
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maxWidth: maxWidth,
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writer: w,
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}
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}
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func (m maxWidthWriter) Write(p []byte) (nn int, err error) {
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for _, b := range p {
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if m.currentWidth == m.maxWidth {
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m.writer.Write([]byte{'\n'})
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m.currentWidth = 0
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}
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if b == '\n' {
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m.currentWidth = 0
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}
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_, err := m.writer.Write([]byte{b})
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if err != nil {
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return int(m.written), err
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}
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m.written++
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m.currentWidth++
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}
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return len(p), nil
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}
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98
pkg/util/term/term_writer_test.go
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98
pkg/util/term/term_writer_test.go
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@ -0,0 +1,98 @@
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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package term
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import (
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"bytes"
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"strings"
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"testing"
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)
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const test = "Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube Kube"
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func TestWordWrapWriter(t *testing.T) {
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testcases := map[string]struct {
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input string
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maxWidth uint
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}{
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"max 10": {input: test, maxWidth: 10},
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"max 80": {input: test, maxWidth: 80},
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"max 120": {input: test, maxWidth: 120},
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"max 5000": {input: test, maxWidth: 5000},
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}
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for k, tc := range testcases {
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b := bytes.NewBufferString("")
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w := NewWordWrapWriter(b, tc.maxWidth)
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_, err := w.Write([]byte(tc.input))
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if err != nil {
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t.Errorf("%s: Unexpected error: %v", k, err)
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}
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result := b.String()
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if !strings.Contains(result, "Kube") {
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t.Errorf("%s: Expected to contain \"Kube\"", k)
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}
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if len(result) < len(tc.input) {
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t.Errorf("%s: Unexpectedly short string, got %d wanted at least %d chars: %q", k, len(result), len(tc.input), result)
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}
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for _, line := range strings.Split(result, "\n") {
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if len(line) > int(tc.maxWidth) {
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t.Errorf("%s: Every line must be at most %d chars long, got %d: %q", k, tc.maxWidth, len(line), line)
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}
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}
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for _, word := range strings.Split(result, " ") {
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if !strings.Contains(word, "Kube") {
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t.Errorf("%s: Unexpected broken word: %q", k, word)
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}
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}
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}
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}
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func TestMaxWidthWriter(t *testing.T) {
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testcases := map[string]struct {
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input string
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maxWidth uint
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}{
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"max 10": {input: test, maxWidth: 10},
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"max 80": {input: test, maxWidth: 80},
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"max 120": {input: test, maxWidth: 120},
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"max 5000": {input: test, maxWidth: 5000},
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}
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for k, tc := range testcases {
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b := bytes.NewBufferString("")
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w := NewMaxWidthWriter(b, tc.maxWidth)
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_, err := w.Write([]byte(tc.input))
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if err != nil {
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t.Errorf("%s: Unexpected error: %v", k, err)
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}
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result := b.String()
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if !strings.Contains(result, "Kube") {
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t.Errorf("%s: Expected to contain \"Kube\"", k)
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}
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if len(result) < len(tc.input) {
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t.Errorf("%s: Unexpectedly short string, got %d wanted at least %d chars: %q", k, len(result), len(tc.input), result)
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}
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lines := strings.Split(result, "\n")
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for i, line := range lines {
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if len(line) > int(tc.maxWidth) {
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t.Errorf("%s: Every line must be at most %d chars long, got %d: %q", k, tc.maxWidth, len(line), line)
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}
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if i < len(lines)-1 && len(line) != int(tc.maxWidth) {
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t.Errorf("%s: Lines except the last one are expected to be exactly %d chars long, got %d: %q", k, tc.maxWidth, len(line), line)
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}
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}
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}
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}
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