helper: implement native container backend

Signed-off-by: Ophestra <cat@gensokyo.uk>

helper/container_test.go

@@ -0,0 +1,55 @@
+package helper_test
+
+import (
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"testing"
+
+	"git.gensokyo.uk/security/fortify/helper"
+	"git.gensokyo.uk/security/fortify/internal"
+	"git.gensokyo.uk/security/fortify/internal/sandbox"
+)
+
+func TestContainer(t *testing.T) {
+	t.Run("start empty container", func(t *testing.T) {
+		h := helper.New(context.Background(), "/nonexistent", argsWt, false, argF, nil, nil)
+
+		wantErr := "sandbox: starting an empty container"
+		if err := h.Start(); err == nil || err.Error() != wantErr {
+			t.Errorf("Start: error = %v, wantErr %q",
+				err, wantErr)
+		}
+	})
+
+	t.Run("valid new helper nil check", func(t *testing.T) {
+		if got := helper.New(context.TODO(), "fortify", argsWt, false, argF, nil, nil); got == nil {
+			t.Errorf("New(%q, %q) got nil",
+				argsWt, "fortify")
+			return
+		}
+	})
+
+	t.Run("implementation compliance", func(t *testing.T) {
+		testHelper(t, func(ctx context.Context, setOutput func(stdoutP, stderrP *io.Writer), stat bool) helper.Helper {
+			return helper.New(ctx, os.Args[0], argsWt, stat, argF, func(container *sandbox.Container) {
+				setOutput(&container.Stdout, &container.Stderr)
+				container.CommandContext = func(ctx context.Context) (cmd *exec.Cmd) {
+					return exec.CommandContext(ctx, os.Args[0], "-test.v",
+						"-test.run=TestHelperInit", "--", "init")
+				}
+				container.Bind("/", "/", 0)
+				container.Proc("/proc")
+				container.Dev("/dev")
+			}, nil)
+		})
+	})
+}
+
+func TestHelperInit(t *testing.T) {
+	if len(os.Args) != 5 || os.Args[4] != "init" {
+		return
+	}
+	sandbox.Init(internal.Exit)
+}