chore: import tests from gnolang#1257 (h/t @jaekwon)

Signed-off-by: moul <94029+moul@users.noreply.github.com>

examples/gno.land/p/demo/tests/p_crossrealm/p_crossrealm.gno

@@ -0,0 +1,24 @@
+package p_crossrealm
+
+type Stringer interface {
+	String() string
+}
+
+type Container struct {
+	A int
+	B Stringer
+}
+
+func (c *Container) Touch() *Container {
+	c.A += 1
+	return c
+}
+
+func (c *Container) Print() {
+	println("A:", c.A)
+	if c.B == nil {
+		println("B: undefined")
+	} else {
+		println("B:", c.B.String())
+	}
+}

examples/gno.land/r/demo/tests/crossrealm/crossrealm.gno

@@ -0,0 +1,29 @@
+package crossrealm
+
+import (
+	"gno.land/p/demo/tests/p_crossrealm"
+	"gno.land/p/demo/ufmt"
+)
+
+type LocalStruct struct {
+	A int
+}
+
+func (ls *LocalStruct) String() string {
+	return ufmt.Sprintf("LocalStruct{%d}", ls.A)
+}
+
+// local is saved locally in this realm
+var local *LocalStruct
+
+func init() {
+	local = &LocalStruct{A: 123}
+}
+
+// Make1 returns a local object wrapped by a p struct
+func Make1() *p_crossrealm.Container {
+	return &p_crossrealm.Container{
+		A: 1,
+		B: local,
+	}
+}

gnovm/tests/files/zrealm_crossrealm13.gno

@@ -0,0 +1,17 @@
+// PKGPATH: gno.land/r/crossrealm_test
+package crossrealm_test
+
+import (
+	crossrealm "gno.land/r/demo/tests/crossrealm"
+)
+
+func main() {
+	// even though we are running within a realm,
+	// we aren't storing the result of crossrealm.Make1(),
+	// so this should print fine.
+	crossrealm.Make1().Touch().Print()
+}
+
+// Output:
+// A: 2
+// B: LocalStruct{123}