test: add basic integration tests

Signed-off-by: Justin Chadwell <me@jedevc.com>

tests/ls.go

@@ -0,0 +1,33 @@
+package tests
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/moby/buildkit/util/testutil/integration"
+	"github.com/stretchr/testify/require"
+)
+
+func lsCmd(sb integration.Sandbox, args ...string) (string, error) {
+	args = append([]string{"ls"}, args...)
+	cmd := buildxCmd(sb, args...)
+	out, err := cmd.CombinedOutput()
+	return string(out), err
+}
+
+var lsTests = []func(t *testing.T, sb integration.Sandbox){
+	testLs,
+}
+
+func testLs(t *testing.T, sb integration.Sandbox) {
+	out, err := lsCmd(sb)
+	require.NoError(t, err, string(out))
+
+	for _, line := range strings.Split(out, "\n") {
+		if strings.Contains(line, sb.Address()) {
+			require.Contains(t, line, sb.Name())
+			return
+		}
+	}
+	require.Fail(t, out)
+}