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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:15:26 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:15:26 +0000 |
commit | 82539ad8d59729fb45b0bb0edda8f2bddb719eb1 (patch) | |
tree | 58f0b58e6f44f0e04d4a6373132cf426fa835fa7 /src/bufio/scan_test.go | |
parent | Initial commit. (diff) | |
download | golang-1.17-82539ad8d59729fb45b0bb0edda8f2bddb719eb1.tar.xz golang-1.17-82539ad8d59729fb45b0bb0edda8f2bddb719eb1.zip |
Adding upstream version 1.17.13.upstream/1.17.13upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/bufio/scan_test.go')
-rw-r--r-- | src/bufio/scan_test.go | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/src/bufio/scan_test.go b/src/bufio/scan_test.go new file mode 100644 index 0000000..e99b09f --- /dev/null +++ b/src/bufio/scan_test.go @@ -0,0 +1,596 @@ +// Copyright 2013 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package bufio_test + +import ( + . "bufio" + "bytes" + "errors" + "io" + "strings" + "testing" + "unicode" + "unicode/utf8" +) + +const smallMaxTokenSize = 256 // Much smaller for more efficient testing. + +// Test white space table matches the Unicode definition. +func TestSpace(t *testing.T) { + for r := rune(0); r <= utf8.MaxRune; r++ { + if IsSpace(r) != unicode.IsSpace(r) { + t.Fatalf("white space property disagrees: %#U should be %t", r, unicode.IsSpace(r)) + } + } +} + +var scanTests = []string{ + "", + "a", + "¼", + "☹", + "\x81", // UTF-8 error + "\uFFFD", // correctly encoded RuneError + "abcdefgh", + "abc def\n\t\tgh ", + "abc¼☹\x81\uFFFD日本語\x82abc", +} + +func TestScanByte(t *testing.T) { + for n, test := range scanTests { + buf := strings.NewReader(test) + s := NewScanner(buf) + s.Split(ScanBytes) + var i int + for i = 0; s.Scan(); i++ { + if b := s.Bytes(); len(b) != 1 || b[0] != test[i] { + t.Errorf("#%d: %d: expected %q got %q", n, i, test, b) + } + } + if i != len(test) { + t.Errorf("#%d: termination expected at %d; got %d", n, len(test), i) + } + err := s.Err() + if err != nil { + t.Errorf("#%d: %v", n, err) + } + } +} + +// Test that the rune splitter returns same sequence of runes (not bytes) as for range string. +func TestScanRune(t *testing.T) { + for n, test := range scanTests { + buf := strings.NewReader(test) + s := NewScanner(buf) + s.Split(ScanRunes) + var i, runeCount int + var expect rune + // Use a string range loop to validate the sequence of runes. + for i, expect = range string(test) { + if !s.Scan() { + break + } + runeCount++ + got, _ := utf8.DecodeRune(s.Bytes()) + if got != expect { + t.Errorf("#%d: %d: expected %q got %q", n, i, expect, got) + } + } + if s.Scan() { + t.Errorf("#%d: scan ran too long, got %q", n, s.Text()) + } + testRuneCount := utf8.RuneCountInString(test) + if runeCount != testRuneCount { + t.Errorf("#%d: termination expected at %d; got %d", n, testRuneCount, runeCount) + } + err := s.Err() + if err != nil { + t.Errorf("#%d: %v", n, err) + } + } +} + +var wordScanTests = []string{ + "", + " ", + "\n", + "a", + " a ", + "abc def", + " abc def ", + " abc\tdef\nghi\rjkl\fmno\vpqr\u0085stu\u00a0\n", +} + +// Test that the word splitter returns the same data as strings.Fields. +func TestScanWords(t *testing.T) { + for n, test := range wordScanTests { + buf := strings.NewReader(test) + s := NewScanner(buf) + s.Split(ScanWords) + words := strings.Fields(test) + var wordCount int + for wordCount = 0; wordCount < len(words); wordCount++ { + if !s.Scan() { + break + } + got := s.Text() + if got != words[wordCount] { + t.Errorf("#%d: %d: expected %q got %q", n, wordCount, words[wordCount], got) + } + } + if s.Scan() { + t.Errorf("#%d: scan ran too long, got %q", n, s.Text()) + } + if wordCount != len(words) { + t.Errorf("#%d: termination expected at %d; got %d", n, len(words), wordCount) + } + err := s.Err() + if err != nil { + t.Errorf("#%d: %v", n, err) + } + } +} + +// slowReader is a reader that returns only a few bytes at a time, to test the incremental +// reads in Scanner.Scan. +type slowReader struct { + max int + buf io.Reader +} + +func (sr *slowReader) Read(p []byte) (n int, err error) { + if len(p) > sr.max { + p = p[0:sr.max] + } + return sr.buf.Read(p) +} + +// genLine writes to buf a predictable but non-trivial line of text of length +// n, including the terminal newline and an occasional carriage return. +// If addNewline is false, the \r and \n are not emitted. +func genLine(buf *bytes.Buffer, lineNum, n int, addNewline bool) { + buf.Reset() + doCR := lineNum%5 == 0 + if doCR { + n-- + } + for i := 0; i < n-1; i++ { // Stop early for \n. + c := 'a' + byte(lineNum+i) + if c == '\n' || c == '\r' { // Don't confuse us. + c = 'N' + } + buf.WriteByte(c) + } + if addNewline { + if doCR { + buf.WriteByte('\r') + } + buf.WriteByte('\n') + } +} + +// Test the line splitter, including some carriage returns but no long lines. +func TestScanLongLines(t *testing.T) { + // Build a buffer of lots of line lengths up to but not exceeding smallMaxTokenSize. + tmp := new(bytes.Buffer) + buf := new(bytes.Buffer) + lineNum := 0 + j := 0 + for i := 0; i < 2*smallMaxTokenSize; i++ { + genLine(tmp, lineNum, j, true) + if j < smallMaxTokenSize { + j++ + } else { + j-- + } + buf.Write(tmp.Bytes()) + lineNum++ + } + s := NewScanner(&slowReader{1, buf}) + s.Split(ScanLines) + s.MaxTokenSize(smallMaxTokenSize) + j = 0 + for lineNum := 0; s.Scan(); lineNum++ { + genLine(tmp, lineNum, j, false) + if j < smallMaxTokenSize { + j++ + } else { + j-- + } + line := tmp.String() // We use the string-valued token here, for variety. + if s.Text() != line { + t.Errorf("%d: bad line: %d %d\n%.100q\n%.100q\n", lineNum, len(s.Bytes()), len(line), s.Text(), line) + } + } + err := s.Err() + if err != nil { + t.Fatal(err) + } +} + +// Test that the line splitter errors out on a long line. +func TestScanLineTooLong(t *testing.T) { + const smallMaxTokenSize = 256 // Much smaller for more efficient testing. + // Build a buffer of lots of line lengths up to but not exceeding smallMaxTokenSize. + tmp := new(bytes.Buffer) + buf := new(bytes.Buffer) + lineNum := 0 + j := 0 + for i := 0; i < 2*smallMaxTokenSize; i++ { + genLine(tmp, lineNum, j, true) + j++ + buf.Write(tmp.Bytes()) + lineNum++ + } + s := NewScanner(&slowReader{3, buf}) + s.Split(ScanLines) + s.MaxTokenSize(smallMaxTokenSize) + j = 0 + for lineNum := 0; s.Scan(); lineNum++ { + genLine(tmp, lineNum, j, false) + if j < smallMaxTokenSize { + j++ + } else { + j-- + } + line := tmp.Bytes() + if !bytes.Equal(s.Bytes(), line) { + t.Errorf("%d: bad line: %d %d\n%.100q\n%.100q\n", lineNum, len(s.Bytes()), len(line), s.Bytes(), line) + } + } + err := s.Err() + if err != ErrTooLong { + t.Fatalf("expected ErrTooLong; got %s", err) + } +} + +// Test that the line splitter handles a final line without a newline. +func testNoNewline(text string, lines []string, t *testing.T) { + buf := strings.NewReader(text) + s := NewScanner(&slowReader{7, buf}) + s.Split(ScanLines) + for lineNum := 0; s.Scan(); lineNum++ { + line := lines[lineNum] + if s.Text() != line { + t.Errorf("%d: bad line: %d %d\n%.100q\n%.100q\n", lineNum, len(s.Bytes()), len(line), s.Bytes(), line) + } + } + err := s.Err() + if err != nil { + t.Fatal(err) + } +} + +// Test that the line splitter handles a final line without a newline. +func TestScanLineNoNewline(t *testing.T) { + const text = "abcdefghijklmn\nopqrstuvwxyz" + lines := []string{ + "abcdefghijklmn", + "opqrstuvwxyz", + } + testNoNewline(text, lines, t) +} + +// Test that the line splitter handles a final line with a carriage return but no newline. +func TestScanLineReturnButNoNewline(t *testing.T) { + const text = "abcdefghijklmn\nopqrstuvwxyz\r" + lines := []string{ + "abcdefghijklmn", + "opqrstuvwxyz", + } + testNoNewline(text, lines, t) +} + +// Test that the line splitter handles a final empty line. +func TestScanLineEmptyFinalLine(t *testing.T) { + const text = "abcdefghijklmn\nopqrstuvwxyz\n\n" + lines := []string{ + "abcdefghijklmn", + "opqrstuvwxyz", + "", + } + testNoNewline(text, lines, t) +} + +// Test that the line splitter handles a final empty line with a carriage return but no newline. +func TestScanLineEmptyFinalLineWithCR(t *testing.T) { + const text = "abcdefghijklmn\nopqrstuvwxyz\n\r" + lines := []string{ + "abcdefghijklmn", + "opqrstuvwxyz", + "", + } + testNoNewline(text, lines, t) +} + +var testError = errors.New("testError") + +// Test the correct error is returned when the split function errors out. +func TestSplitError(t *testing.T) { + // Create a split function that delivers a little data, then a predictable error. + numSplits := 0 + const okCount = 7 + errorSplit := func(data []byte, atEOF bool) (advance int, token []byte, err error) { + if atEOF { + panic("didn't get enough data") + } + if numSplits >= okCount { + return 0, nil, testError + } + numSplits++ + return 1, data[0:1], nil + } + // Read the data. + const text = "abcdefghijklmnopqrstuvwxyz" + buf := strings.NewReader(text) + s := NewScanner(&slowReader{1, buf}) + s.Split(errorSplit) + var i int + for i = 0; s.Scan(); i++ { + if len(s.Bytes()) != 1 || text[i] != s.Bytes()[0] { + t.Errorf("#%d: expected %q got %q", i, text[i], s.Bytes()[0]) + } + } + // Check correct termination location and error. + if i != okCount { + t.Errorf("unexpected termination; expected %d tokens got %d", okCount, i) + } + err := s.Err() + if err != testError { + t.Fatalf("expected %q got %v", testError, err) + } +} + +// Test that an EOF is overridden by a user-generated scan error. +func TestErrAtEOF(t *testing.T) { + s := NewScanner(strings.NewReader("1 2 33")) + // This splitter will fail on last entry, after s.err==EOF. + split := func(data []byte, atEOF bool) (advance int, token []byte, err error) { + advance, token, err = ScanWords(data, atEOF) + if len(token) > 1 { + if s.ErrOrEOF() != io.EOF { + t.Fatal("not testing EOF") + } + err = testError + } + return + } + s.Split(split) + for s.Scan() { + } + if s.Err() != testError { + t.Fatal("wrong error:", s.Err()) + } +} + +// Test for issue 5268. +type alwaysError struct{} + +func (alwaysError) Read(p []byte) (int, error) { + return 0, io.ErrUnexpectedEOF +} + +func TestNonEOFWithEmptyRead(t *testing.T) { + scanner := NewScanner(alwaysError{}) + for scanner.Scan() { + t.Fatal("read should fail") + } + err := scanner.Err() + if err != io.ErrUnexpectedEOF { + t.Errorf("unexpected error: %v", err) + } +} + +// Test that Scan finishes if we have endless empty reads. +type endlessZeros struct{} + +func (endlessZeros) Read(p []byte) (int, error) { + return 0, nil +} + +func TestBadReader(t *testing.T) { + scanner := NewScanner(endlessZeros{}) + for scanner.Scan() { + t.Fatal("read should fail") + } + err := scanner.Err() + if err != io.ErrNoProgress { + t.Errorf("unexpected error: %v", err) + } +} + +func TestScanWordsExcessiveWhiteSpace(t *testing.T) { + const word = "ipsum" + s := strings.Repeat(" ", 4*smallMaxTokenSize) + word + scanner := NewScanner(strings.NewReader(s)) + scanner.MaxTokenSize(smallMaxTokenSize) + scanner.Split(ScanWords) + if !scanner.Scan() { + t.Fatalf("scan failed: %v", scanner.Err()) + } + if token := scanner.Text(); token != word { + t.Fatalf("unexpected token: %v", token) + } +} + +// Test that empty tokens, including at end of line or end of file, are found by the scanner. +// Issue 8672: Could miss final empty token. + +func commaSplit(data []byte, atEOF bool) (advance int, token []byte, err error) { + for i := 0; i < len(data); i++ { + if data[i] == ',' { + return i + 1, data[:i], nil + } + } + return 0, data, ErrFinalToken +} + +func testEmptyTokens(t *testing.T, text string, values []string) { + s := NewScanner(strings.NewReader(text)) + s.Split(commaSplit) + var i int + for i = 0; s.Scan(); i++ { + if i >= len(values) { + t.Fatalf("got %d fields, expected %d", i+1, len(values)) + } + if s.Text() != values[i] { + t.Errorf("%d: expected %q got %q", i, values[i], s.Text()) + } + } + if i != len(values) { + t.Fatalf("got %d fields, expected %d", i, len(values)) + } + if err := s.Err(); err != nil { + t.Fatal(err) + } +} + +func TestEmptyTokens(t *testing.T) { + testEmptyTokens(t, "1,2,3,", []string{"1", "2", "3", ""}) +} + +func TestWithNoEmptyTokens(t *testing.T) { + testEmptyTokens(t, "1,2,3", []string{"1", "2", "3"}) +} + +func loopAtEOFSplit(data []byte, atEOF bool) (advance int, token []byte, err error) { + if len(data) > 0 { + return 1, data[:1], nil + } + return 0, data, nil +} + +func TestDontLoopForever(t *testing.T) { + s := NewScanner(strings.NewReader("abc")) + s.Split(loopAtEOFSplit) + // Expect a panic + defer func() { + err := recover() + if err == nil { + t.Fatal("should have panicked") + } + if msg, ok := err.(string); !ok || !strings.Contains(msg, "empty tokens") { + panic(err) + } + }() + for count := 0; s.Scan(); count++ { + if count > 1000 { + t.Fatal("looping") + } + } + if s.Err() != nil { + t.Fatal("after scan:", s.Err()) + } +} + +func TestBlankLines(t *testing.T) { + s := NewScanner(strings.NewReader(strings.Repeat("\n", 1000))) + for count := 0; s.Scan(); count++ { + if count > 2000 { + t.Fatal("looping") + } + } + if s.Err() != nil { + t.Fatal("after scan:", s.Err()) + } +} + +type countdown int + +func (c *countdown) split(data []byte, atEOF bool) (advance int, token []byte, err error) { + if *c > 0 { + *c-- + return 1, data[:1], nil + } + return 0, nil, nil +} + +// Check that the looping-at-EOF check doesn't trigger for merely empty tokens. +func TestEmptyLinesOK(t *testing.T) { + c := countdown(10000) + s := NewScanner(strings.NewReader(strings.Repeat("\n", 10000))) + s.Split(c.split) + for s.Scan() { + } + if s.Err() != nil { + t.Fatal("after scan:", s.Err()) + } + if c != 0 { + t.Fatalf("stopped with %d left to process", c) + } +} + +// Make sure we can read a huge token if a big enough buffer is provided. +func TestHugeBuffer(t *testing.T) { + text := strings.Repeat("x", 2*MaxScanTokenSize) + s := NewScanner(strings.NewReader(text + "\n")) + s.Buffer(make([]byte, 100), 3*MaxScanTokenSize) + for s.Scan() { + token := s.Text() + if token != text { + t.Errorf("scan got incorrect token of length %d", len(token)) + } + } + if s.Err() != nil { + t.Fatal("after scan:", s.Err()) + } +} + +// negativeEOFReader returns an invalid -1 at the end, as though it +// were wrapping the read system call. +type negativeEOFReader int + +func (r *negativeEOFReader) Read(p []byte) (int, error) { + if *r > 0 { + c := int(*r) + if c > len(p) { + c = len(p) + } + for i := 0; i < c; i++ { + p[i] = 'a' + } + p[c-1] = '\n' + *r -= negativeEOFReader(c) + return c, nil + } + return -1, io.EOF +} + +// Test that the scanner doesn't panic and returns ErrBadReadCount +// on a reader that returns a negative count of bytes read (issue 38053). +func TestNegativeEOFReader(t *testing.T) { + r := negativeEOFReader(10) + scanner := NewScanner(&r) + c := 0 + for scanner.Scan() { + c++ + if c > 1 { + t.Error("read too many lines") + break + } + } + if got, want := scanner.Err(), ErrBadReadCount; got != want { + t.Errorf("scanner.Err: got %v, want %v", got, want) + } +} + +// largeReader returns an invalid count that is larger than the number +// of bytes requested. +type largeReader struct{} + +func (largeReader) Read(p []byte) (int, error) { + return len(p) + 1, nil +} + +// Test that the scanner doesn't panic and returns ErrBadReadCount +// on a reader that returns an impossibly large count of bytes read (issue 38053). +func TestLargeReader(t *testing.T) { + scanner := NewScanner(largeReader{}) + for scanner.Scan() { + } + if got, want := scanner.Err(), ErrBadReadCount; got != want { + t.Errorf("scanner.Err: got %v, want %v", got, want) + } +} |