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| 1 | +// Copyright 2018 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 | +// This file implements a regression test harness for syntax errors. |
| 6 | +// The files in the testdata directory are parsed and the reported |
| 7 | +// errors are compared against the errors declared in those files. |
| 8 | +// |
| 9 | +// Errors are declared in place in the form of "error comments", |
| 10 | +// just before (or on the same line as) the offending token. |
| 11 | +// |
| 12 | +// Error comments must be of the form // ERROR rx or /* ERROR rx */ |
| 13 | +// where rx is a regular expression that matches the reported error |
| 14 | +// message. The rx text comprises the comment text after "ERROR ", |
| 15 | +// with any white space around it stripped. |
| 16 | +// |
| 17 | +// If the line comment form is used, the reported error's line must |
| 18 | +// match the line of the error comment. |
| 19 | +// |
| 20 | +// If the regular comment form is used, the reported error's position |
| 21 | +// must match the position of the token immediately following the |
| 22 | +// error comment. Thus, /* ERROR ... */ comments should appear |
| 23 | +// immediately before the position where the error is reported. |
| 24 | +// |
| 25 | +// Currently, the test harness only supports one error comment per |
| 26 | +// token. If multiple error comments appear before a token, only |
| 27 | +// the last one is considered. |
| 28 | + |
| 29 | +package syntax |
| 30 | + |
| 31 | +import ( |
| 32 | + "flag" |
| 33 | + "fmt" |
| 34 | + "internal/testenv" |
| 35 | + "io/ioutil" |
| 36 | + "os" |
| 37 | + "path/filepath" |
| 38 | + "regexp" |
| 39 | + "sort" |
| 40 | + "strings" |
| 41 | + "testing" |
| 42 | +) |
| 43 | + |
| 44 | +const testdata = "testdata" // directory containing test files |
| 45 | + |
| 46 | +var print = flag.Bool("print", false, "only print errors") |
| 47 | + |
| 48 | +// A position represents a source position in the current file. |
| 49 | +type position struct { |
| 50 | + line, col uint |
| 51 | +} |
| 52 | + |
| 53 | +func (pos position) String() string { |
| 54 | + return fmt.Sprintf("%d:%d", pos.line, pos.col) |
| 55 | +} |
| 56 | + |
| 57 | +func sortedPositions(m map[position]string) []position { |
| 58 | + list := make([]position, len(m)) |
| 59 | + i := 0 |
| 60 | + for pos := range m { |
| 61 | + list[i] = pos |
| 62 | + i++ |
| 63 | + } |
| 64 | + sort.Slice(list, func(i, j int) bool { |
| 65 | + a, b := list[i], list[j] |
| 66 | + return a.line < b.line || a.line == b.line && a.col < b.col |
| 67 | + }) |
| 68 | + return list |
| 69 | +} |
| 70 | + |
| 71 | +// declaredErrors returns a map of source positions to error |
| 72 | +// patterns, extracted from error comments in the given file. |
| 73 | +// Error comments in the form of line comments use col = 0 |
| 74 | +// in their position. |
| 75 | +func declaredErrors(t *testing.T, filename string) map[position]string { |
| 76 | + f, err := os.Open(filename) |
| 77 | + if err != nil { |
| 78 | + t.Fatal(err) |
| 79 | + } |
| 80 | + defer f.Close() |
| 81 | + |
| 82 | + declared := make(map[position]string) |
| 83 | + |
| 84 | + var s scanner |
| 85 | + var pattern string |
| 86 | + s.init(f, func(line, col uint, msg string) { |
| 87 | + // errors never start with '/' so they are automatically excluded here |
| 88 | + switch { |
| 89 | + case strings.HasPrefix(msg, "// ERROR "): |
| 90 | + // we can't have another comment on the same line - just add it |
| 91 | + declared[position{s.line, 0}] = strings.TrimSpace(msg[9:]) |
| 92 | + case strings.HasPrefix(msg, "/* ERROR "): |
| 93 | + // we may have more comments before the next token - collect them |
| 94 | + pattern = strings.TrimSpace(msg[9 : len(msg)-2]) |
| 95 | + } |
| 96 | + }, comments) |
| 97 | + |
| 98 | + // consume file |
| 99 | + for { |
| 100 | + s.next() |
| 101 | + if pattern != "" { |
| 102 | + declared[position{s.line, s.col}] = pattern |
| 103 | + pattern = "" |
| 104 | + } |
| 105 | + if s.tok == _EOF { |
| 106 | + break |
| 107 | + } |
| 108 | + } |
| 109 | + |
| 110 | + return declared |
| 111 | +} |
| 112 | + |
| 113 | +func testSyntaxErrors(t *testing.T, filename string) { |
| 114 | + declared := declaredErrors(t, filename) |
| 115 | + if *print { |
| 116 | + fmt.Println("Declared errors:") |
| 117 | + for _, pos := range sortedPositions(declared) { |
| 118 | + fmt.Printf("%s:%s: %s\n", filename, pos, declared[pos]) |
| 119 | + } |
| 120 | + |
| 121 | + fmt.Println() |
| 122 | + fmt.Println("Reported errors:") |
| 123 | + } |
| 124 | + |
| 125 | + f, err := os.Open(filename) |
| 126 | + if err != nil { |
| 127 | + t.Fatal(err) |
| 128 | + } |
| 129 | + defer f.Close() |
| 130 | + |
| 131 | + ParseFile(filename, func(err error) { |
| 132 | + e, ok := err.(Error) |
| 133 | + if !ok { |
| 134 | + return |
| 135 | + } |
| 136 | + |
| 137 | + if *print { |
| 138 | + fmt.Println(err) |
| 139 | + return |
| 140 | + } |
| 141 | + |
| 142 | + orig := position{e.Pos.Line(), e.Pos.Col()} |
| 143 | + pos := orig |
| 144 | + pattern, found := declared[pos] |
| 145 | + if !found { |
| 146 | + // try line comment (only line must match) |
| 147 | + pos = position{e.Pos.Line(), 0} |
| 148 | + pattern, found = declared[pos] |
| 149 | + } |
| 150 | + if found { |
| 151 | + rx, err := regexp.Compile(pattern) |
| 152 | + if err != nil { |
| 153 | + t.Errorf("%s: %v", pos, err) |
| 154 | + return |
| 155 | + } |
| 156 | + if match := rx.MatchString(e.Msg); !match { |
| 157 | + t.Errorf("%s: %q does not match %q", pos, e.Msg, pattern) |
| 158 | + return |
| 159 | + } |
| 160 | + // we have a match - eliminate this error |
| 161 | + delete(declared, pos) |
| 162 | + } else { |
| 163 | + t.Errorf("%s: unexpected error: %s", orig, e.Msg) |
| 164 | + } |
| 165 | + }, nil, 0) |
| 166 | + |
| 167 | + if *print { |
| 168 | + fmt.Println() |
| 169 | + return // we're done |
| 170 | + } |
| 171 | + |
| 172 | + // report expected but not reported errors |
| 173 | + for pos, pattern := range declared { |
| 174 | + t.Errorf("%s: missing error: %s", pos, pattern) |
| 175 | + } |
| 176 | +} |
| 177 | + |
| 178 | +func TestSyntaxErrors(t *testing.T) { |
| 179 | + testenv.MustHaveGoBuild(t) // we need access to source (testdata) |
| 180 | + |
| 181 | + list, err := ioutil.ReadDir(testdata) |
| 182 | + if err != nil { |
| 183 | + t.Fatal(err) |
| 184 | + } |
| 185 | + for _, fi := range list { |
| 186 | + name := fi.Name() |
| 187 | + if !fi.IsDir() && !strings.HasPrefix(name, ".") { |
| 188 | + testSyntaxErrors(t, filepath.Join(testdata, name)) |
| 189 | + } |
| 190 | + } |
| 191 | +} |
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