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Source file src/reflect/set_test.go

Documentation: reflect

  // Copyright 2011 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 reflect_test
  
  import (
  	"bytes"
  	"go/ast"
  	"go/token"
  	"io"
  	. "reflect"
  	"testing"
  	"unsafe"
  )
  
  type MyBuffer bytes.Buffer
  
  func TestImplicitMapConversion(t *testing.T) {
  	// Test implicit conversions in MapIndex and SetMapIndex.
  	{
  		// direct
  		m := make(map[int]int)
  		mv := ValueOf(m)
  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
  		x, ok := m[1]
  		if x != 2 {
  			t.Errorf("#1 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
  		}
  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
  			t.Errorf("#1 MapIndex(1) = %d", n)
  		}
  	}
  	{
  		// convert interface key
  		m := make(map[interface{}]int)
  		mv := ValueOf(m)
  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
  		x, ok := m[1]
  		if x != 2 {
  			t.Errorf("#2 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
  		}
  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
  			t.Errorf("#2 MapIndex(1) = %d", n)
  		}
  	}
  	{
  		// convert interface value
  		m := make(map[int]interface{})
  		mv := ValueOf(m)
  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
  		x, ok := m[1]
  		if x != 2 {
  			t.Errorf("#3 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
  		}
  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
  			t.Errorf("#3 MapIndex(1) = %d", n)
  		}
  	}
  	{
  		// convert both interface key and interface value
  		m := make(map[interface{}]interface{})
  		mv := ValueOf(m)
  		mv.SetMapIndex(ValueOf(1), ValueOf(2))
  		x, ok := m[1]
  		if x != 2 {
  			t.Errorf("#4 after SetMapIndex(1,2): %d, %t (map=%v)", x, ok, m)
  		}
  		if n := mv.MapIndex(ValueOf(1)).Interface().(int); n != 2 {
  			t.Errorf("#4 MapIndex(1) = %d", n)
  		}
  	}
  	{
  		// convert both, with non-empty interfaces
  		m := make(map[io.Reader]io.Writer)
  		mv := ValueOf(m)
  		b1 := new(bytes.Buffer)
  		b2 := new(bytes.Buffer)
  		mv.SetMapIndex(ValueOf(b1), ValueOf(b2))
  		x, ok := m[b1]
  		if x != b2 {
  			t.Errorf("#5 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
  		}
  		if p := mv.MapIndex(ValueOf(b1)).Elem().Pointer(); p != uintptr(unsafe.Pointer(b2)) {
  			t.Errorf("#5 MapIndex(b1) = %#x want %p", p, b2)
  		}
  	}
  	{
  		// convert channel direction
  		m := make(map[<-chan int]chan int)
  		mv := ValueOf(m)
  		c1 := make(chan int)
  		c2 := make(chan int)
  		mv.SetMapIndex(ValueOf(c1), ValueOf(c2))
  		x, ok := m[c1]
  		if x != c2 {
  			t.Errorf("#6 after SetMapIndex(c1, c2): %p (!= %p), %t (map=%v)", x, c2, ok, m)
  		}
  		if p := mv.MapIndex(ValueOf(c1)).Pointer(); p != ValueOf(c2).Pointer() {
  			t.Errorf("#6 MapIndex(c1) = %#x want %p", p, c2)
  		}
  	}
  	{
  		// convert identical underlying types
  		// TODO(rsc): Should be able to define MyBuffer here.
  		// 6l prints very strange messages about .this.Bytes etc
  		// when we do that though, so MyBuffer is defined
  		// at top level.
  		m := make(map[*MyBuffer]*bytes.Buffer)
  		mv := ValueOf(m)
  		b1 := new(MyBuffer)
  		b2 := new(bytes.Buffer)
  		mv.SetMapIndex(ValueOf(b1), ValueOf(b2))
  		x, ok := m[b1]
  		if x != b2 {
  			t.Errorf("#7 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
  		}
  		if p := mv.MapIndex(ValueOf(b1)).Pointer(); p != uintptr(unsafe.Pointer(b2)) {
  			t.Errorf("#7 MapIndex(b1) = %#x want %p", p, b2)
  		}
  	}
  
  }
  
  func TestImplicitSetConversion(t *testing.T) {
  	// Assume TestImplicitMapConversion covered the basics.
  	// Just make sure conversions are being applied at all.
  	var r io.Reader
  	b := new(bytes.Buffer)
  	rv := ValueOf(&r).Elem()
  	rv.Set(ValueOf(b))
  	if r != b {
  		t.Errorf("after Set: r=%T(%v)", r, r)
  	}
  }
  
  func TestImplicitSendConversion(t *testing.T) {
  	c := make(chan io.Reader, 10)
  	b := new(bytes.Buffer)
  	ValueOf(c).Send(ValueOf(b))
  	if bb := <-c; bb != b {
  		t.Errorf("Received %p != %p", bb, b)
  	}
  }
  
  func TestImplicitCallConversion(t *testing.T) {
  	// Arguments must be assignable to parameter types.
  	fv := ValueOf(io.WriteString)
  	b := new(bytes.Buffer)
  	fv.Call([]Value{ValueOf(b), ValueOf("hello world")})
  	if b.String() != "hello world" {
  		t.Errorf("After call: string=%q want %q", b.String(), "hello world")
  	}
  }
  
  func TestImplicitAppendConversion(t *testing.T) {
  	// Arguments must be assignable to the slice's element type.
  	s := []io.Reader{}
  	sv := ValueOf(&s).Elem()
  	b := new(bytes.Buffer)
  	sv.Set(Append(sv, ValueOf(b)))
  	if len(s) != 1 || s[0] != b {
  		t.Errorf("after append: s=%v want [%p]", s, b)
  	}
  }
  
  var implementsTests = []struct {
  	x interface{}
  	t interface{}
  	b bool
  }{
  	{new(*bytes.Buffer), new(io.Reader), true},
  	{new(bytes.Buffer), new(io.Reader), false},
  	{new(*bytes.Buffer), new(io.ReaderAt), false},
  	{new(*ast.Ident), new(ast.Expr), true},
  	{new(*notAnExpr), new(ast.Expr), false},
  	{new(*ast.Ident), new(notASTExpr), false},
  	{new(notASTExpr), new(ast.Expr), false},
  	{new(ast.Expr), new(notASTExpr), false},
  	{new(*notAnExpr), new(notASTExpr), true},
  }
  
  type notAnExpr struct{}
  
  func (notAnExpr) Pos() token.Pos { return token.NoPos }
  func (notAnExpr) End() token.Pos { return token.NoPos }
  func (notAnExpr) exprNode()      {}
  
  type notASTExpr interface {
  	Pos() token.Pos
  	End() token.Pos
  	exprNode()
  }
  
  func TestImplements(t *testing.T) {
  	for _, tt := range implementsTests {
  		xv := TypeOf(tt.x).Elem()
  		xt := TypeOf(tt.t).Elem()
  		if b := xv.Implements(xt); b != tt.b {
  			t.Errorf("(%s).Implements(%s) = %v, want %v", xv.String(), xt.String(), b, tt.b)
  		}
  	}
  }
  
  var assignableTests = []struct {
  	x interface{}
  	t interface{}
  	b bool
  }{
  	{new(chan int), new(<-chan int), true},
  	{new(<-chan int), new(chan int), false},
  	{new(*int), new(IntPtr), true},
  	{new(IntPtr), new(*int), true},
  	{new(IntPtr), new(IntPtr1), false},
  	{new(Ch), new(<-chan interface{}), true},
  	// test runs implementsTests too
  }
  
  type IntPtr *int
  type IntPtr1 *int
  type Ch <-chan interface{}
  
  func TestAssignableTo(t *testing.T) {
  	for _, tt := range append(assignableTests, implementsTests...) {
  		xv := TypeOf(tt.x).Elem()
  		xt := TypeOf(tt.t).Elem()
  		if b := xv.AssignableTo(xt); b != tt.b {
  			t.Errorf("(%s).AssignableTo(%s) = %v, want %v", xv.String(), xt.String(), b, tt.b)
  		}
  	}
  }
  

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