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// Copyright 2012 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 format
import (
"bytes"
"go/ast"
"go/parser"
"go/token"
"os"
"strings"
"testing"
)
const testfile = "format_test.go"
func diff(t *testing.T, dst, src []byte) {
line := 1
offs := 0 // line offset
for i := 0; i < len(dst) && i < len(src); i++ {
d := dst[i]
s := src[i]
if d != s {
t.Errorf("dst:%d: %s\n", line, dst[offs:i+1])
t.Errorf("src:%d: %s\n", line, src[offs:i+1])
return
}
if s == '\n' {
line++
offs = i + 1
}
}
if len(dst) != len(src) {
t.Errorf("len(dst) = %d, len(src) = %d\nsrc = %q", len(dst), len(src), src)
}
}
func TestNode(t *testing.T) {
src, err := os.ReadFile(testfile)
if err != nil {
t.Fatal(err)
}
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, testfile, src, parser.ParseComments)
if err != nil {
t.Fatal(err)
}
var buf bytes.Buffer
if err = Node(&buf, fset, file); err != nil {
t.Fatal("Node failed:", err)
}
diff(t, buf.Bytes(), src)
}
// Node is documented to not modify the AST.
// Test that it is so even when numbers are normalized.
func TestNodeNoModify(t *testing.T) {
const (
src = "package p\n\nconst _ = 0000000123i\n"
golden = "package p\n\nconst _ = 123i\n"
)
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "", src, parser.ParseComments)
if err != nil {
t.Fatal(err)
}
// Capture original address and value of a BasicLit node
// which will undergo formatting changes during printing.
wantLit := file.Decls[0].(*ast.GenDecl).Specs[0].(*ast.ValueSpec).Values[0].(*ast.BasicLit)
wantVal := wantLit.Value
var buf bytes.Buffer
if err = Node(&buf, fset, file); err != nil {
t.Fatal("Node failed:", err)
}
diff(t, buf.Bytes(), []byte(golden))
// Check if anything changed after Node returned.
gotLit := file.Decls[0].(*ast.GenDecl).Specs[0].(*ast.ValueSpec).Values[0].(*ast.BasicLit)
gotVal := gotLit.Value
if gotLit != wantLit {
t.Errorf("got *ast.BasicLit address %p, want %p", gotLit, wantLit)
}
if gotVal != wantVal {
t.Errorf("got *ast.BasicLit value %q, want %q", gotVal, wantVal)
}
}
func TestSource(t *testing.T) {
src, err := os.ReadFile(testfile)
if err != nil {
t.Fatal(err)
}
res, err := Source(src)
if err != nil {
t.Fatal("Source failed:", err)
}
diff(t, res, src)
}
// Test cases that are expected to fail are marked by the prefix "ERROR".
// The formatted result must look the same as the input for successful tests.
var tests = []string{
// declaration lists
`import "go/format"`,
"var x int",
"var x int\n\ntype T struct{}",
// statement lists
"x := 0",
"f(a, b, c)\nvar x int = f(1, 2, 3)",
// indentation, leading and trailing space
"\tx := 0\n\tgo f()",
"\tx := 0\n\tgo f()\n\n\n",
"\n\t\t\n\n\tx := 0\n\tgo f()\n\n\n",
"\n\t\t\n\n\t\t\tx := 0\n\t\t\tgo f()\n\n\n",
"\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
"\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
// comments
"/* Comment */",
"\t/* Comment */ ",
"\n/* Comment */ ",
"i := 5 /* Comment */", // issue #5551
"\ta()\n//line :1", // issue #11276
"\t//xxx\n\ta()\n//line :2", // issue #11276
"\ta() //line :1\n\tb()\n", // issue #11276
"x := 0\n//line :1\n//line :2", // issue #11276
// whitespace
"", // issue #11275
" ", // issue #11275
"\t", // issue #11275
"\t\t", // issue #11275
"\n", // issue #11275
"\n\n", // issue #11275
"\t\n", // issue #11275
// erroneous programs
"ERROR1 + 2 +",
"ERRORx := 0",
}
func String(s string) (string, error) {
res, err := Source([]byte(s))
if err != nil {
return "", err
}
return string(res), nil
}
func TestPartial(t *testing.T) {
for _, src := range tests {
if strings.HasPrefix(src, "ERROR") {
// test expected to fail
src = src[5:] // remove ERROR prefix
res, err := String(src)
if err == nil && res == src {
t.Errorf("formatting succeeded but was expected to fail:\n%q", src)
}
} else {
// test expected to succeed
res, err := String(src)
if err != nil {
t.Errorf("formatting failed (%s):\n%q", err, src)
} else if res != src {
t.Errorf("formatting incorrect:\nsource: %q\nresult: %q", src, res)
}
}
}
}
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