icu_test.go

Documentation: golang.org/x/text/cases

     1  // Copyright 2016 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  //go:build icu
     6  
     7  package cases
     8  
     9  import (
    10  	"path"
    11  	"strings"
    12  	"testing"
    13  
    14  	"golang.org/x/text/language"
    15  	"golang.org/x/text/unicode/norm"
    16  )
    17  
    18  func TestICUConformance(t *testing.T) {
    19  	// Build test set.
    20  	input := []string{
    21  		"a.a a_a",
    22  		"a\u05d0a",
    23  		"\u05d0'a",
    24  		"a\u03084a",
    25  		"a\u0308a",
    26  		"a3\u30a3a",
    27  		"a\u303aa",
    28  		"a_\u303a_a",
    29  		"1_a..a",
    30  		"1_a.a",
    31  		"a..a.",
    32  		"a--a-",
    33  		"a-a-",
    34  		"a\u200ba",
    35  		"a\u200b\u200ba",
    36  		"a\u00ad\u00ada", // Format
    37  		"a\u00ada",
    38  		"a''a", // SingleQuote
    39  		"a'a",
    40  		"a::a", // MidLetter
    41  		"a:a",
    42  		"a..a", // MidNumLet
    43  		"a.a",
    44  		"a;;a", // MidNum
    45  		"a;a",
    46  		"a__a", // ExtendNumlet
    47  		"a_a",
    48  		"ΟΣ''a",
    49  	}
    50  	add := func(x interface{}) {
    51  		switch v := x.(type) {
    52  		case string:
    53  			input = append(input, v)
    54  		case []string:
    55  			for _, s := range v {
    56  				input = append(input, s)
    57  			}
    58  		}
    59  	}
    60  	for _, tc := range testCases {
    61  		add(tc.src)
    62  		add(tc.lower)
    63  		add(tc.upper)
    64  		add(tc.title)
    65  	}
    66  	for _, tc := range bufferTests {
    67  		add(tc.src)
    68  	}
    69  	for _, tc := range breakTest {
    70  		add(strings.Replace(tc, "|", "", -1))
    71  	}
    72  	for _, tc := range foldTestCases {
    73  		add(tc)
    74  	}
    75  
    76  	// Compare ICU to Go.
    77  	for _, c := range []string{"lower", "upper", "title", "fold"} {
    78  		for _, tag := range []string{
    79  			"und", "af", "az", "el", "lt", "nl", "tr",
    80  		} {
    81  			for _, s := range input {
    82  				if exclude(c, tag, s) {
    83  					continue
    84  				}
    85  				t.Run(path.Join(c, tag, s), func(t *testing.T) {
    86  					want := doICU(tag, c, s)
    87  					got := doGo(tag, c, s)
    88  					if norm.NFC.String(got) != norm.NFC.String(want) {
    89  						t.Errorf("\n    in %[3]q (%+[3]q)\n   got %[1]q (%+[1]q)\n  want %[2]q (%+[2]q)", got, want, s)
    90  					}
    91  				})
    92  			}
    93  		}
    94  	}
    95  }
    96  
    97  // exclude indicates if a string should be excluded from testing.
    98  func exclude(cm, tag, s string) bool {
    99  	list := []struct{ cm, tags, pattern string }{
   100  		// TODO: Go does not handle certain esoteric breaks correctly. This will be
   101  		// fixed once we have a real word break iterator. Alternatively, it
   102  		// seems like we're not too far off from making it work, so we could
   103  		// fix these last steps. But first verify that using a separate word
   104  		// breaker does not hurt performance.
   105  		{"title", "af nl", "a''a"},
   106  		{"", "", "א'a"},
   107  
   108  		// All the exclusions below seem to be issues with the ICU
   109  		// implementation (at version 57) and thus are not marked as TODO.
   110  
   111  		// ICU does not handle leading apostrophe for Dutch and
   112  		// Afrikaans correctly. See https://unicode.org/cldr/trac/ticket/7078.
   113  		{"title", "af nl", "'n"},
   114  		{"title", "af nl", "'N"},
   115  
   116  		// Go terminates the final sigma check after a fixed number of
   117  		// ignorables have been found. This ensures that the algorithm can make
   118  		// progress in a streaming scenario.
   119  		{"lower title", "", "\u039f\u03a3...............................a"},
   120  		// This also applies to upper in Greek.
   121  		// NOTE: we could fix the following two cases by adding state to elUpper
   122  		// and aztrLower. However, considering a modifier to not belong to the
   123  		// preceding letter after the maximum modifiers count is reached is
   124  		// consistent with the behavior of unicode/norm.
   125  		{"upper", "el", "\u03bf" + strings.Repeat("\u0321", 29) + "\u0313"},
   126  		{"lower", "az tr lt", "I" + strings.Repeat("\u0321", 30) + "\u0307\u0300"},
   127  		{"upper", "lt", "i" + strings.Repeat("\u0321", 30) + "\u0307\u0300"},
   128  		{"lower", "lt", "I" + strings.Repeat("\u0321", 30) + "\u0300"},
   129  
   130  		// ICU title case seems to erroneously removes \u0307 from an upper case
   131  		// I unconditionally, instead of only when lowercasing. The ICU
   132  		// transform algorithm transforms these cases consistently with our
   133  		// implementation.
   134  		{"title", "az tr", "\u0307"},
   135  
   136  		// The spec says to remove \u0307 after Soft-Dotted characters. ICU
   137  		// transforms conform but ucasemap_utf8ToUpper does not.
   138  		{"upper title", "lt", "i\u0307"},
   139  		{"upper title", "lt", "i" + strings.Repeat("\u0321", 29) + "\u0307\u0300"},
   140  
   141  		// Both Unicode and CLDR prescribe an extra explicit dot above after a
   142  		// Soft_Dotted character if there are other modifiers.
   143  		// ucasemap_utf8ToUpper does not do this; ICU transforms do.
   144  		// The issue with ucasemap_utf8ToUpper seems to be that it does not
   145  		// consider the modifiers that are part of composition in the evaluation
   146  		// of More_Above. For instance, according to the More_Above rule for lt,
   147  		// a dotted capital I (U+0130) becomes i\u0307\u0307 (an small i with
   148  		// two additional dots). This seems odd, but is correct. ICU is
   149  		// definitely not correct as it produces different results for different
   150  		// normal forms. For instance, for an İ:
   151  		//    \u0130  (NFC) -> i\u0307         (incorrect)
   152  		//    I\u0307 (NFD) -> i\u0307\u0307   (correct)
   153  		// We could argue that we should not add a \u0307 if there already is
   154  		// one, but this may be hard to get correct and is not conform the
   155  		// standard.
   156  		{"lower title", "lt", "\u0130"},
   157  		{"lower title", "lt", "\u00cf"},
   158  
   159  		// We are conform ICU ucasemap_utf8ToUpper if we remove support for
   160  		// elUpper. However, this is clearly not conform the spec. Moreover, the
   161  		// ICU transforms _do_ implement this transform and produces results
   162  		// consistent with our implementation. Note that we still prefer to use
   163  		// ucasemap_utf8ToUpper instead of transforms as the latter have
   164  		// inconsistencies in the word breaking algorithm.
   165  		{"upper", "el", "\u0386"}, // GREEK CAPITAL LETTER ALPHA WITH TONOS
   166  		{"upper", "el", "\u0389"}, // GREEK CAPITAL LETTER ETA WITH TONOS
   167  		{"upper", "el", "\u038A"}, // GREEK CAPITAL LETTER IOTA WITH TONOS
   168  
   169  		{"upper", "el", "\u0391"}, // GREEK CAPITAL LETTER ALPHA
   170  		{"upper", "el", "\u0397"}, // GREEK CAPITAL LETTER ETA
   171  		{"upper", "el", "\u0399"}, // GREEK CAPITAL LETTER IOTA
   172  
   173  		{"upper", "el", "\u03AC"}, // GREEK SMALL LETTER ALPHA WITH TONOS
   174  		{"upper", "el", "\u03AE"}, // GREEK SMALL LETTER ALPHA WITH ETA
   175  		{"upper", "el", "\u03AF"}, // GREEK SMALL LETTER ALPHA WITH IOTA
   176  
   177  		{"upper", "el", "\u03B1"}, // GREEK SMALL LETTER ALPHA
   178  		{"upper", "el", "\u03B7"}, // GREEK SMALL LETTER ETA
   179  		{"upper", "el", "\u03B9"}, // GREEK SMALL LETTER IOTA
   180  	}
   181  	for _, x := range list {
   182  		if x.cm != "" && strings.Index(x.cm, cm) == -1 {
   183  			continue
   184  		}
   185  		if x.tags != "" && strings.Index(x.tags, tag) == -1 {
   186  			continue
   187  		}
   188  		if strings.Index(s, x.pattern) != -1 {
   189  			return true
   190  		}
   191  	}
   192  	return false
   193  }
   194  
   195  func doGo(tag, caser, input string) string {
   196  	var c Caser
   197  	t := language.MustParse(tag)
   198  	switch caser {
   199  	case "lower":
   200  		c = Lower(t)
   201  	case "upper":
   202  		c = Upper(t)
   203  	case "title":
   204  		c = Title(t)
   205  	case "fold":
   206  		c = Fold()
   207  	}
   208  	return c.String(input)
   209  }
   210
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