assertEqualCharNodes(traverser.breadthFirst(charactersOf("acdb")), "acdb");
    assertEqualCharNodes(traverser.breadthFirst(charactersOf("db")), "db");
  }

  @Test
  public void forGraph_breadthFirst_multiGraph() {
    Traverser<Character> traverser = Traverser.forGraph(MULTI_GRAPH);
    assertEqualCharNodes(traverser.breadthFirst('a'), "abcd");

		err               error
	}{
		0: {
			desc:       "Success, no checksum verification provided.",
			src:        bytes.NewReader([]byte("abcd")),
			size:       4,
			actualSize: 4,
		},
		{
			desc:       "Failure md5 mismatch.",
			src:        bytes.NewReader([]byte("abcd")),
			size:       4,
			actualSize: 4,
			md5hex:     "d41d8cd98f00b204e9800998ecf8427f",
			err: BadDigest{

		commonPrefix string
	}{
		{[]string{"", ""}, ""},
		{[]string{"a", "b"}, ""},
		{[]string{"a", "a"}, "a"},
		{[]string{"a/", "a/"}, "a/"},
		{[]string{"abcd/", ""}, ""},
		{[]string{"abcd/foo/", "abcd/bar/"}, "abcd/"},
		{[]string{"abcd/foo/bar/", "abcd/foo/bar/zoo"}, "abcd/foo/bar/"},
	}

	for i, test := range testCases {
		foundPrefix := lcp(test.prefixes, true)
		if foundPrefix != test.commonPrefix {

		9: {
			bucketName: bucket, objName: object, inputData: []byte("abcd"),
			inputMeta: map[string]string{"etag": "900150983cd24fb0d6963f7d28e17f73"}, inputDataSize: int64(len("abcd") - 1),
			expectedError: ioutil.ErrOverread,
		},

		// Validating for success cases.

    assertEquals("", Strings.commonPrefix("abc", ""));
    assertEquals("", Strings.commonPrefix("", "abc"));
    assertEquals("", Strings.commonPrefix("abcde", "xyz"));
    assertEquals("", Strings.commonPrefix("xyz", "abcde"));
    assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));

    val relay = edit(file, upstream, metadata, 5)
    val source1 = relay.newSource()!!.buffer()
    val source2 = relay.newSource()!!.buffer()
    assertThat(source1.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.exhausted()).isTrue()

func TestEvalSQLSubstring(t *testing.T) {
	evalCases := []struct {
		s           string
		startIdx    int
		length      int
		resExpected string
		errExpected error
	}{
		{"abcd", 1, 1, "a", nil},
		{"abcd", -1, 1, "a", nil},
		{"abcd", 999, 999, "", nil},
		{"", 999, 999, "", nil},
		{"测试abc", 1, 1, "测", nil},
		{"测试abc", 5, 5, "c", nil},
	}

	for i, tc := range evalCases {

	if err != nil {
		t.Fatal(err)
	}
	// Upload a good object
	_, err = obj.DeleteObject(ctx, bucket, object, ObjectOptions{})
	if err != nil {
		t.Fatal(err)
	}

	// Create "obj" under "bucket".
	_, err = obj.PutObject(ctx, bucket, object, mustGetPutObjReader(t, bytes.NewReader([]byte("abcd")), int64(len("abcd")), "", ""), opts)

		},
		// Test Case - 4.
		// Test case with AccessKey of length 2.
		{
			inputCredentialStr: generateCredentialStr(
				"^#",
				UTCNow().Format(yyyymmdd),
				"ABCD",
				"ABCD",
				"ABCD"),
			expectedCredentials: credentialHeader{},
			expectedErrCode:     ErrInvalidAccessKeyID,
		},
		// Test Case - 5.
		// Test case with invalid date format date.

		t.Fatalf("expect 4 abcd but got %s. r.w=%d, r.r=%d", rb.Bytes(nil), rb.w, rb.r)
	}

	// check empty or full
	if rb.IsEmpty() {
		t.Fatalf("expect IsEmpty is false but got true")
	}
	if rb.IsFull() {
		t.Fatalf("expect IsFull is false but got true")
	}

	// write 48 bytes, should full
	n, err = rb.Write([]byte(strings.Repeat("abcd", 12)))
	if err != nil {