Merge pull request #2078 from yichengq/290

pkg/crc: add test

pkg/crc/crc_test.go

@@ -0,0 +1,59 @@
+// Copyright 2009 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 crc
+
+import (
+	"hash/crc32"
+	"reflect"
+	"testing"
+)
+
+// TestHash32 tests that Hash32 provided by this package can take an initial
+// crc and behaves exactly the same as the standard one in the following calls.
+func TestHash32(t *testing.T) {
+	stdhash := crc32.New(crc32.IEEETable)
+	if _, err := stdhash.Write([]byte("test data")); err != nil {
+		t.Fatalf("unexpected write error: %v", err)
+	}
+	// create a new hash with stdhash.Sum32() as initial crc
+	hash := New(stdhash.Sum32(), crc32.IEEETable)
+
+	wsize := stdhash.Size()
+	if g := hash.Size(); g != wsize {
+		t.Errorf("size = %d, want %d", g, wsize)
+	}
+	wbsize := stdhash.BlockSize()
+	if g := hash.BlockSize(); g != wbsize {
+		t.Errorf("block size = %d, want %d", g, wbsize)
+	}
+	wsum32 := stdhash.Sum32()
+	if g := hash.Sum32(); g != wsum32 {
+		t.Errorf("Sum32 = %d, want %d", g, wsum32)
+	}
+	wsum := stdhash.Sum(make([]byte, 32))
+	if g := hash.Sum(make([]byte, 32)); !reflect.DeepEqual(g, wsum) {
+		t.Errorf("sum = %v, want %v", g, wsum)
+	}
+
+	// write something
+	if _, err := stdhash.Write([]byte("test data")); err != nil {
+		t.Fatalf("unexpected write error: %v", err)
+	}
+	if _, err := hash.Write([]byte("test data")); err != nil {
+		t.Fatalf("unexpected write error: %v", err)
+	}
+	wsum32 = stdhash.Sum32()
+	if g := hash.Sum32(); g != wsum32 {
+		t.Errorf("Sum32 after write = %d, want %d", g, wsum32)
+	}
+
+	// reset
+	stdhash.Reset()
+	hash.Reset()
+	wsum32 = stdhash.Sum32()
+	if g := hash.Sum32(); g != wsum32 {
+		t.Errorf("Sum32 after reset = %d, want %d", g, wsum32)
+	}
+}