swarm: codebase split from go-ethereum (#1405)

testutil/file.go

@@ -0,0 +1,65 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package testutil
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"strings"
+	"testing"
+)
+
+// TempFileWithContent is a helper function that creates a temp file that contains the following string content then closes the file handle
+// it returns the complete file path
+func TempFileWithContent(t *testing.T, content string) string {
+	tempFile, err := ioutil.TempFile("", "swarm-temp-file")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = io.Copy(tempFile, strings.NewReader(content))
+	if err != nil {
+		os.RemoveAll(tempFile.Name())
+		t.Fatal(err)
+	}
+	if err = tempFile.Close(); err != nil {
+		t.Fatal(err)
+	}
+	return tempFile.Name()
+}
+
+// RandomBytes returns pseudo-random deterministic result
+// because test fails must be reproducible
+func RandomBytes(seed, length int) []byte {
+	b := make([]byte, length)
+	reader := rand.New(rand.NewSource(int64(seed)))
+	for n := 0; n < length; {
+		read, err := reader.Read(b[n:])
+		if err != nil {
+			panic(err)
+		}
+		n += read
+	}
+	return b
+}
+
+func RandomReader(seed, length int) *bytes.Reader {
+	return bytes.NewReader(RandomBytes(seed, length))
+}