libgo: update to Go1.16beta1 release

This does not yet include support for the //go:embed directive added
in this release.

	* Makefile.am (check-runtime): Don't create check-runtime-dir.
	(mostlyclean-local): Don't remove check-runtime-dir.
	(check-go-tool, check-vet): Copy in go.mod and modules.txt.
	(check-cgo-test, check-carchive-test): Add go.mod file.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/280172

1 files changed, 35 insertions, 0 deletions

diff --git a/libgo/go/testing/iotest/reader_test.go b/libgo/go/testing/iotest/reader_test.go
index 9397837..f149e74 100644
--- a/libgo/go/testing/iotest/reader_test.go
+++ b/libgo/go/testing/iotest/reader_test.go
@@ -6,7 +6,9 @@ package iotest
 
 import (
 	"bytes"
+	"errors"
 	"io"
+	"strings"
 	"testing"
 )
 
@@ -224,3 +226,36 @@ func TestDataErrReader_emptyReader(t *testing.T) {
 		t.Errorf("Unexpectedly read %d bytes, wanted %d", g, w)
 	}
 }
+
+func TestErrReader(t *testing.T) {
+	cases := []struct {
+		name string
+		err  error
+	}{
+		{"nil error", nil},
+		{"non-nil error", errors.New("io failure")},
+		{"io.EOF", io.EOF},
+	}
+
+	for _, tt := range cases {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			n, err := ErrReader(tt.err).Read(nil)
+			if err != tt.err {
+				t.Fatalf("Error mismatch\nGot:  %v\nWant: %v", err, tt.err)
+			}
+			if n != 0 {
+				t.Fatalf("Byte count mismatch: got %d want 0", n)
+			}
+		})
+	}
+}
+
+func TestStringsReader(t *testing.T) {
+	const msg = "Now is the time for all good gophers."
+
+	r := strings.NewReader(msg)
+	if err := TestReader(r, []byte(msg)); err != nil {
+		t.Fatal(err)
+	}
+}