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Run Format

Source file src/go/format/format_test.go

Documentation: go/format

     1  // Copyright 2012 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  package format
     6  
     7  import (
     8  	"bytes"
     9  	"go/parser"
    10  	"go/token"
    11  	"io/ioutil"
    12  	"strings"
    13  	"testing"
    14  )
    15  
    16  const testfile = "format_test.go"
    17  
    18  func diff(t *testing.T, dst, src []byte) {
    19  	line := 1
    20  	offs := 0 // line offset
    21  	for i := 0; i < len(dst) && i < len(src); i++ {
    22  		d := dst[i]
    23  		s := src[i]
    24  		if d != s {
    25  			t.Errorf("dst:%d: %s\n", line, dst[offs:i+1])
    26  			t.Errorf("src:%d: %s\n", line, src[offs:i+1])
    27  			return
    28  		}
    29  		if s == '\n' {
    30  			line++
    31  			offs = i + 1
    32  		}
    33  	}
    34  	if len(dst) != len(src) {
    35  		t.Errorf("len(dst) = %d, len(src) = %d\nsrc = %q", len(dst), len(src), src)
    36  	}
    37  }
    38  
    39  func TestNode(t *testing.T) {
    40  	src, err := ioutil.ReadFile(testfile)
    41  	if err != nil {
    42  		t.Fatal(err)
    43  	}
    44  
    45  	fset := token.NewFileSet()
    46  	file, err := parser.ParseFile(fset, testfile, src, parser.ParseComments)
    47  	if err != nil {
    48  		t.Fatal(err)
    49  	}
    50  
    51  	var buf bytes.Buffer
    52  
    53  	if err = Node(&buf, fset, file); err != nil {
    54  		t.Fatal("Node failed:", err)
    55  	}
    56  
    57  	diff(t, buf.Bytes(), src)
    58  }
    59  
    60  func TestSource(t *testing.T) {
    61  	src, err := ioutil.ReadFile(testfile)
    62  	if err != nil {
    63  		t.Fatal(err)
    64  	}
    65  
    66  	res, err := Source(src)
    67  	if err != nil {
    68  		t.Fatal("Source failed:", err)
    69  	}
    70  
    71  	diff(t, res, src)
    72  }
    73  
    74  // Test cases that are expected to fail are marked by the prefix "ERROR".
    75  // The formatted result must look the same as the input for successful tests.
    76  var tests = []string{
    77  	// declaration lists
    78  	`import "go/format"`,
    79  	"var x int",
    80  	"var x int\n\ntype T struct{}",
    81  
    82  	// statement lists
    83  	"x := 0",
    84  	"f(a, b, c)\nvar x int = f(1, 2, 3)",
    85  
    86  	// indentation, leading and trailing space
    87  	"\tx := 0\n\tgo f()",
    88  	"\tx := 0\n\tgo f()\n\n\n",
    89  	"\n\t\t\n\n\tx := 0\n\tgo f()\n\n\n",
    90  	"\n\t\t\n\n\t\t\tx := 0\n\t\t\tgo f()\n\n\n",
    91  	"\n\t\t\n\n\t\t\tx := 0\n\t\t\tconst s = `\nfoo\n`\n\n\n",     // no indentation added inside raw strings
    92  	"\n\t\t\n\n\t\t\tx := 0\n\t\t\tconst s = `\n\t\tfoo\n`\n\n\n", // no indentation removed inside raw strings
    93  
    94  	// comments
    95  	"/* Comment */",
    96  	"\t/* Comment */ ",
    97  	"\n/* Comment */ ",
    98  	"i := 5 /* Comment */",         // issue #5551
    99  	"\ta()\n//line :1",             // issue #11276
   100  	"\t//xxx\n\ta()\n//line :2",    // issue #11276
   101  	"\ta() //line :1\n\tb()\n",     // issue #11276
   102  	"x := 0\n//line :1\n//line :2", // issue #11276
   103  
   104  	// whitespace
   105  	"",     // issue #11275
   106  	" ",    // issue #11275
   107  	"\t",   // issue #11275
   108  	"\t\t", // issue #11275
   109  	"\n",   // issue #11275
   110  	"\n\n", // issue #11275
   111  	"\t\n", // issue #11275
   112  
   113  	// erroneous programs
   114  	"ERROR1 + 2 +",
   115  	"ERRORx :=  0",
   116  }
   117  
   118  func String(s string) (string, error) {
   119  	res, err := Source([]byte(s))
   120  	if err != nil {
   121  		return "", err
   122  	}
   123  	return string(res), nil
   124  }
   125  
   126  func TestPartial(t *testing.T) {
   127  	for _, src := range tests {
   128  		if strings.HasPrefix(src, "ERROR") {
   129  			// test expected to fail
   130  			src = src[5:] // remove ERROR prefix
   131  			res, err := String(src)
   132  			if err == nil && res == src {
   133  				t.Errorf("formatting succeeded but was expected to fail:\n%q", src)
   134  			}
   135  		} else {
   136  			// test expected to succeed
   137  			res, err := String(src)
   138  			if err != nil {
   139  				t.Errorf("formatting failed (%s):\n%q", err, src)
   140  			} else if res != src {
   141  				t.Errorf("formatting incorrect:\nsource: %q\nresult: %q", src, res)
   142  			}
   143  		}
   144  	}
   145  }
   146  

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