1 files changed, 92 insertions, 0 deletions
diff --git a/src/embed/internal/embedtest/embedx_test.go b/src/embed/internal/embedtest/embedx_test.go
new file mode 100644
index 0000000..27fa116
--- /dev/null
+++ b/src/embed/internal/embedtest/embedx_test.go
@@ -0,0 +1,92 @@
+// Copyright 2020 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 embedtest_test
+
+import (
+	"embed"
+	"os"
+	"testing"
+)
+
+var (
+	global2      = global
+	concurrency2 = concurrency
+	glass2       = glass
+	sbig2        = sbig
+	bbig2        = bbig
+)
+
+//go:embed testdata/*.txt
+var global embed.FS
+
+//go:embed c*txt
+var concurrency string
+
+//go:embed testdata/g*.txt
+var glass []byte
+
+//go:embed testdata/ascii.txt
+var sbig string
+
+//go:embed testdata/ascii.txt
+var bbig []byte
+
+func testFiles(t *testing.T, f embed.FS, name, data string) {
+	t.Helper()
+	d, err := f.ReadFile(name)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if string(d) != data {
+		t.Errorf("read %v = %q, want %q", name, d, data)
+	}
+}
+
+func testString(t *testing.T, s, name, data string) {
+	t.Helper()
+	if s != data {
+		t.Errorf("%v = %q, want %q", name, s, data)
+	}
+}
+
+func TestXGlobal(t *testing.T) {
+	testFiles(t, global, "testdata/hello.txt", "hello, world\n")
+	testString(t, concurrency, "concurrency", "Concurrency is not parallelism.\n")
+	testString(t, string(glass), "glass", "I can eat glass and it doesn't hurt me.\n")
+	testString(t, concurrency2, "concurrency2", "Concurrency is not parallelism.\n")
+	testString(t, string(glass2), "glass2", "I can eat glass and it doesn't hurt me.\n")
+
+	big, err := os.ReadFile("testdata/ascii.txt")
+	if err != nil {
+		t.Fatal(err)
+	}
+	testString(t, sbig, "sbig", string(big))
+	testString(t, sbig2, "sbig2", string(big))
+	testString(t, string(bbig), "bbig", string(big))
+	testString(t, string(bbig2), "bbig", string(big))
+
+	if t.Failed() {
+		return
+	}
+
+	// Could check &glass[0] == &glass2[0] but also want to make sure write does not fault
+	// (data must not be in read-only memory).
+	old := glass[0]
+	glass[0]++
+	if glass2[0] != glass[0] {
+		t.Fatalf("glass and glass2 do not share storage")
+	}
+	glass[0] = old
+
+	// Could check &bbig[0] == &bbig2[0] but also want to make sure write does not fault
+	// (data must not be in read-only memory).
+	old = bbig[0]
+	bbig[0]++
+	if bbig2[0] != bbig[0] {
+		t.Fatalf("bbig and bbig2 do not share storage")
+	}
+	bbig[0] = old
+}