Golang Map.Len方法代码示例

func checkTypesExpectation(e *expectation, pts pointer.PointsToSet, typ types.Type) bool {
	var expected typeutil.Map
	var surplus typeutil.Map
	exact := true
	for _, g := range e.types {
		if g == types.Typ[types.Invalid] {
			exact = false
			continue
		}
		expected.Set(g, struct{}{})
	}

	if !pointer.CanHaveDynamicTypes(typ) {
		e.errorf("@types expectation requires an interface- or reflect.Value-typed operand, got %s", typ)
		return false
	}

	// Find the set of types that the probe's
	// argument (x in print(x)) may contain.
	for _, T := range pts.DynamicTypes().Keys() {
		if expected.At(T) != nil {
			expected.Delete(T)
		} else if exact {
			surplus.Set(T, struct{}{})
		}
	}
	// Report set difference:
	ok := true
	if expected.Len() > 0 {
		ok = false
		e.errorf("interface cannot contain these types: %s", expected.KeysString())
	}
	if surplus.Len() > 0 {
		ok = false
		e.errorf("interface may additionally contain these types: %s", surplus.KeysString())
	}
	return ok
}

func TestMap(t *testing.T) {
	var tmap *typeutil.Map

	// All methods but Set are safe on on (*T)(nil).
	tmap.Len()
	tmap.At(tPStr1)
	tmap.Delete(tPStr1)
	tmap.KeysString()
	tmap.String()

	tmap = new(typeutil.Map)

	// Length of empty map.
	if l := tmap.Len(); l != 0 {
		t.Errorf("Len() on empty Map: got %d, want 0", l)
	}
	// At of missing key.
	if v := tmap.At(tPStr1); v != nil {
		t.Errorf("At() on empty Map: got %v, want nil", v)
	}
	// Deletion of missing key.
	if tmap.Delete(tPStr1) {
		t.Errorf("Delete() on empty Map: got true, want false")
	}
	// Set of new key.
	if prev := tmap.Set(tPStr1, "*string"); prev != nil {
		t.Errorf("Set() on empty Map returned non-nil previous value %s", prev)
	}

	// Now: {*string: "*string"}

	// Length of non-empty map.
	if l := tmap.Len(); l != 1 {
		t.Errorf("Len(): got %d, want 1", l)
	}
	// At via insertion key.
	if v := tmap.At(tPStr1); v != "*string" {
		t.Errorf("At(): got %q, want \"*string\"", v)
	}
	// At via equal key.
	if v := tmap.At(tPStr2); v != "*string" {
		t.Errorf("At(): got %q, want \"*string\"", v)
	}
	// Iteration over sole entry.
	tmap.Iterate(func(key types.Type, value interface{}) {
		if key != tPStr1 {
			t.Errorf("Iterate: key: got %s, want %s", key, tPStr1)
		}
		if want := "*string"; value != want {
			t.Errorf("Iterate: value: got %s, want %s", value, want)
		}
	})

	// Setion with key equal to present one.
	if prev := tmap.Set(tPStr2, "*string again"); prev != "*string" {
		t.Errorf("Set() previous value: got %s, want \"*string\"", prev)
	}

	// Setion of another association.
	if prev := tmap.Set(tChanInt1, "<-chan int"); prev != nil {
		t.Errorf("Set() previous value: got %s, want nil", prev)
	}

	// Now: {*string: "*string again", <-chan int: "<-chan int"}

	want1 := "{*string: \"*string again\", <-chan int: \"<-chan int\"}"
	want2 := "{<-chan int: \"<-chan int\", *string: \"*string again\"}"
	if s := tmap.String(); s != want1 && s != want2 {
		t.Errorf("String(): got %s, want %s", s, want1)
	}

	want1 = "{*string, <-chan int}"
	want2 = "{<-chan int, *string}"
	if s := tmap.KeysString(); s != want1 && s != want2 {
		t.Errorf("KeysString(): got %s, want %s", s, want1)
	}

	// Keys().
	I := types.Identical
	switch k := tmap.Keys(); {
	case I(k[0], tChanInt1) && I(k[1], tPStr1): // ok
	case I(k[1], tChanInt1) && I(k[0], tPStr1): // ok
	default:
		t.Errorf("Keys(): got %v, want %s", k, want2)
	}

	if l := tmap.Len(); l != 2 {
		t.Errorf("Len(): got %d, want 1", l)
	}
	// At via original key.
	if v := tmap.At(tPStr1); v != "*string again" {
		t.Errorf("At(): got %q, want \"*string again\"", v)
	}
	hamming := 1
	tmap.Iterate(func(key types.Type, value interface{}) {
		switch {
		case I(key, tChanInt1):
			hamming *= 2 // ok
		case I(key, tPStr1):
			hamming *= 3 // ok
//.........这里部分代码省略.........