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Source file src/reflect/set_test.go

Documentation: reflect

     1  // Copyright 2011 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 reflect_test
     6  
     7  import (
     8  	"bytes"
     9  	"go/ast"
    10  	"go/token"
    11  	"io"
    12  	. "reflect"
    13  	"strings"
    14  	"testing"
    15  	"unsafe"
    16  )
    17  
    18  func TestImplicitMapConversion(t *testing.T) {
    19  	// Test implicit conversions in MapIndex and SetMapIndex.
    20  	{
    21  		// direct
    22  		m := make(map[int]int)
    23  		mv := ValueOf(m)
    24  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
    25  		x, ok := m[1]
    26  		if x != 2 {
    27  			t.Errorf("#1 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
    28  		}
    29  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
    30  			t.Errorf("#1 MapIndex(1) = %d", n)
    31  		}
    32  	}
    33  	{
    34  		// convert interface key
    35  		m := make(map[any]int)
    36  		mv := ValueOf(m)
    37  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
    38  		x, ok := m[1]
    39  		if x != 2 {
    40  			t.Errorf("#2 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
    41  		}
    42  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
    43  			t.Errorf("#2 MapIndex(1) = %d", n)
    44  		}
    45  	}
    46  	{
    47  		// convert interface value
    48  		m := make(map[int]any)
    49  		mv := ValueOf(m)
    50  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
    51  		x, ok := m[1]
    52  		if x != 2 {
    53  			t.Errorf("#3 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
    54  		}
    55  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
    56  			t.Errorf("#3 MapIndex(1) = %d", n)
    57  		}
    58  	}
    59  	{
    60  		// convert both interface key and interface value
    61  		m := make(map[any]any)
    62  		mv := ValueOf(m)
    63  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
    64  		x, ok := m[1]
    65  		if x != 2 {
    66  			t.Errorf("#4 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
    67  		}
    68  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
    69  			t.Errorf("#4 MapIndex(1) = %d", n)
    70  		}
    71  	}
    72  	{
    73  		// convert both, with non-empty interfaces
    74  		m := make(map[io.Reader]io.Writer)
    75  		mv := ValueOf(m)
    76  		b1 := new(bytes.Buffer)
    77  		b2 := new(bytes.Buffer)
    78  		mv.SetMapIndex(ValueOf(b1), ValueOf(b2))
    79  		x, ok := m[b1]
    80  		if x != b2 {
    81  			t.Errorf("#5 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
    82  		}
    83  		if p := mv.MapIndex(ValueOf(b1)).Elem().UnsafePointer(); p != unsafe.Pointer(b2) {
    84  			t.Errorf("#5 MapIndex(b1) = %#x want %p", p, b2)
    85  		}
    86  	}
    87  	{
    88  		// convert channel direction
    89  		m := make(map[<-chan int]chan int)
    90  		mv := ValueOf(m)
    91  		c1 := make(chan int)
    92  		c2 := make(chan int)
    93  		mv.SetMapIndex(ValueOf(c1), ValueOf(c2))
    94  		x, ok := m[c1]
    95  		if x != c2 {
    96  			t.Errorf("#6 after SetMapIndex(c1, c2): %p (!= %p), %t (map=%v)", x, c2, ok, m)
    97  		}
    98  		if p := mv.MapIndex(ValueOf(c1)).UnsafePointer(); p != ValueOf(c2).UnsafePointer() {
    99  			t.Errorf("#6 MapIndex(c1) = %#x want %p", p, c2)
   100  		}
   101  	}
   102  	{
   103  		// convert identical underlying types
   104  		type MyBuffer bytes.Buffer
   105  		m := make(map[*MyBuffer]*bytes.Buffer)
   106  		mv := ValueOf(m)
   107  		b1 := new(MyBuffer)
   108  		b2 := new(bytes.Buffer)
   109  		mv.SetMapIndex(ValueOf(b1), ValueOf(b2))
   110  		x, ok := m[b1]
   111  		if x != b2 {
   112  			t.Errorf("#7 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
   113  		}
   114  		if p := mv.MapIndex(ValueOf(b1)).UnsafePointer(); p != unsafe.Pointer(b2) {
   115  			t.Errorf("#7 MapIndex(b1) = %#x want %p", p, b2)
   116  		}
   117  	}
   118  
   119  }
   120  
   121  func TestImplicitSetConversion(t *testing.T) {
   122  	// Assume TestImplicitMapConversion covered the basics.
   123  	// Just make sure conversions are being applied at all.
   124  	var r io.Reader
   125  	b := new(bytes.Buffer)
   126  	rv := ValueOf(&r).Elem()
   127  	rv.Set(ValueOf(b))
   128  	if r != b {
   129  		t.Errorf("after Set: r=%T(%v)", r, r)
   130  	}
   131  }
   132  
   133  func TestImplicitSendConversion(t *testing.T) {
   134  	c := make(chan io.Reader, 10)
   135  	b := new(bytes.Buffer)
   136  	ValueOf(c).Send(ValueOf(b))
   137  	if bb := <-c; bb != b {
   138  		t.Errorf("Received %p != %p", bb, b)
   139  	}
   140  }
   141  
   142  func TestImplicitCallConversion(t *testing.T) {
   143  	// Arguments must be assignable to parameter types.
   144  	fv := ValueOf(io.WriteString)
   145  	b := new(strings.Builder)
   146  	fv.Call([]Value{ValueOf(b), ValueOf("hello world")})
   147  	if b.String() != "hello world" {
   148  		t.Errorf("After call: string=%q want %q", b.String(), "hello world")
   149  	}
   150  }
   151  
   152  func TestImplicitAppendConversion(t *testing.T) {
   153  	// Arguments must be assignable to the slice's element type.
   154  	s := []io.Reader{}
   155  	sv := ValueOf(&s).Elem()
   156  	b := new(bytes.Buffer)
   157  	sv.Set(Append(sv, ValueOf(b)))
   158  	if len(s) != 1 || s[0] != b {
   159  		t.Errorf("after append: s=%v want [%p]", s, b)
   160  	}
   161  }
   162  
   163  var implementsTests = []struct {
   164  	x any
   165  	t any
   166  	b bool
   167  }{
   168  	{new(*bytes.Buffer), new(io.Reader), true},
   169  	{new(bytes.Buffer), new(io.Reader), false},
   170  	{new(*bytes.Buffer), new(io.ReaderAt), false},
   171  	{new(*ast.Ident), new(ast.Expr), true},
   172  	{new(*notAnExpr), new(ast.Expr), false},
   173  	{new(*ast.Ident), new(notASTExpr), false},
   174  	{new(notASTExpr), new(ast.Expr), false},
   175  	{new(ast.Expr), new(notASTExpr), false},
   176  	{new(*notAnExpr), new(notASTExpr), true},
   177  }
   178  
   179  type notAnExpr struct{}
   180  
   181  func (notAnExpr) Pos() token.Pos { return token.NoPos }
   182  func (notAnExpr) End() token.Pos { return token.NoPos }
   183  func (notAnExpr) exprNode()      {}
   184  
   185  type notASTExpr interface {
   186  	Pos() token.Pos
   187  	End() token.Pos
   188  	exprNode()
   189  }
   190  
   191  func TestImplements(t *testing.T) {
   192  	for _, tt := range implementsTests {
   193  		xv := TypeOf(tt.x).Elem()
   194  		xt := TypeOf(tt.t).Elem()
   195  		if b := xv.Implements(xt); b != tt.b {
   196  			t.Errorf("(%s).Implements(%s) = %v, want %v", xv.String(), xt.String(), b, tt.b)
   197  		}
   198  	}
   199  }
   200  
   201  var assignableTests = []struct {
   202  	x any
   203  	t any
   204  	b bool
   205  }{
   206  	{new(chan int), new(<-chan int), true},
   207  	{new(<-chan int), new(chan int), false},
   208  	{new(*int), new(IntPtr), true},
   209  	{new(IntPtr), new(*int), true},
   210  	{new(IntPtr), new(IntPtr1), false},
   211  	{new(Ch), new(<-chan any), true},
   212  	// test runs implementsTests too
   213  }
   214  
   215  type IntPtr *int
   216  type IntPtr1 *int
   217  type Ch <-chan any
   218  
   219  func TestAssignableTo(t *testing.T) {
   220  	for _, tt := range append(assignableTests, implementsTests...) {
   221  		xv := TypeOf(tt.x).Elem()
   222  		xt := TypeOf(tt.t).Elem()
   223  		if b := xv.AssignableTo(xt); b != tt.b {
   224  			t.Errorf("(%s).AssignableTo(%s) = %v, want %v", xv.String(), xt.String(), b, tt.b)
   225  		}
   226  	}
   227  }
   228  

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