tests: cli: add TestZerokey

TestZerokey verifies that `gocryptfs -zerokey` uses the same options as
`gocryptfs -init`.

tests/cli/zerokey.go

@@ -0,0 +1,60 @@
+package cli
+
+import (
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"testing"
+
+	"github.com/rfjakob/gocryptfs/tests/test_helpers"
+)
+
+// TestZerokey verifies that `gocryptfs -zerokey` uses the same options as
+// `gocryptfs -init`.
+func TestZerokey(t *testing.T) {
+	// Create FS
+	dir := test_helpers.InitFS(t)
+
+	// Change masterkey to all-zero using password change
+	args := []string{"-q", "-passwd", "-masterkey",
+		"00000000-00000000-00000000-00000000-00000000-00000000-00000000-00000000"}
+	args = append(args, dir)
+	cmd := exec.Command(test_helpers.GocryptfsBinary, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	p, err := cmd.StdinPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = cmd.Start()
+	if err != nil {
+		t.Error(err)
+	}
+	// New password = old password
+	p.Write([]byte("test\n"))
+	p.Close()
+	err = cmd.Wait()
+	if err != nil {
+		t.Error(err)
+	}
+
+	// Add content
+	mnt := dir + ".mnt"
+	test_helpers.MountOrFatal(t, dir, mnt, "-extpass", "echo test")
+	file1 := mnt + "/file1"
+	err = ioutil.WriteFile(file1, []byte("somecontent"), 0600)
+	if err != nil {
+		t.Fatal(err)
+	}
+	test_helpers.UnmountPanic(mnt)
+
+	// Mount using -zerokey and verify we get the same result
+	test_helpers.MountOrFatal(t, dir, mnt, "-extpass", "echo test")
+	content, err := ioutil.ReadFile(file1)
+	if err != nil {
+		t.Error(err)
+	} else if string(content) != "somecontent" {
+		t.Errorf("wrong content: %q", string(content))
+	}
+	test_helpers.UnmountPanic(mnt)
+}