internal/lsp/regtest: add test for issue 32149 (wrong package)

Gopls gets confused about the package if the package name is edited.
(See golang.org/issues/32149) This skipped test will succeed as long
as the bug is present.

Change-Id: Ic99ceda133f92f306baf94e2f8ad0381ed565814
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227760
Run-TryBot: Peter Weinberger <pjw@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/regtest/diagnostics_test.go

@@ -241,3 +241,21 @@ func Test_Issue38267(t *testing.T) {
 		)
 	})
 }
+
+const packageChange = `
+-- go.mod --
+module fake
+-- a.go --
+package foo
+func main() {}
+`
+
+func TestPackageChange(t *testing.T) {
+	t.Skip("skipping due to golang.org/issues/32149")
+	runner.Run(t, packageChange, func(env *Env) {
+		env.OpenFile("a.go")
+		env.RegexpReplace("a.go", "foo", "foox")
+		// TODO: there should be no error
+		env.Await(EmptyDiagnostics("a.go"))
+	})
+}