diff --git a/libdevcore/FixedHash.h b/libdevcore/FixedHash.h
index c7c551c2b..e9600ed0c 100644
--- a/libdevcore/FixedHash.h
+++ b/libdevcore/FixedHash.h
@@ -102,7 +102,7 @@ public:
 	FixedHash operator&(FixedHash const& _c) const { return FixedHash(*this) &= _c; }
 	FixedHash operator~() const { FixedHash ret; for (unsigned i = 0; i < N; ++i) ret[i] = ~m_data[i]; return ret; }
 
-	/// @returns true if all bytes in @a _c are set in this object.
+	/// @returns true if all one-bits in @a _c are set in this object.
 	bool contains(FixedHash const& _c) const { return (*this & _c) == _c; }
 
 	/// @returns a particular byte from the hash.
diff --git a/test/libdevcore/FixedHash.cpp b/test/libdevcore/FixedHash.cpp
new file mode 100644
index 000000000..9a6ebe0e0
--- /dev/null
+++ b/test/libdevcore/FixedHash.cpp
@@ -0,0 +1,106 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	cpp-ethereum 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/** @file FixedHash.cpp
+ * @author Lefterus <lefteris@ethdev.com>
+ * @date 2015
+ */
+
+#include <libdevcore/FixedHash.h>
+#include "../TestHelper.h"
+
+using namespace std;
+using namespace dev;
+
+namespace dev
+{
+namespace test
+{
+
+BOOST_AUTO_TEST_SUITE(FixedHashTests)
+
+BOOST_AUTO_TEST_CASE(FixedHashComparisons)
+{
+	FixedHash<4> h1(sha3("abcd"));
+	FixedHash<4> h2(sha3("abcd"));
+	FixedHash<4> h3(sha3("aadd"));
+	FixedHash<4> h4(0xBAADF00D);
+	FixedHash<4> h5(0xAAAAAAAA);
+	FixedHash<4> h6(0xBAADF00D);
+
+	BOOST_CHECK(h1 == h2);
+	BOOST_CHECK(h2 != h3);
+
+	BOOST_CHECK(h4 > h5);
+	BOOST_CHECK(h5 < h4);
+	BOOST_CHECK(h6 <= h4);
+	BOOST_CHECK(h6 >= h4);
+}
+
+BOOST_AUTO_TEST_CASE(FixedHashXOR)
+{
+	FixedHash<2> h1("0xAAAA");
+	FixedHash<2> h2("0xBBBB");
+
+	BOOST_CHECK((h1 ^ h2) == FixedHash<2>("0x1111"));
+	h1 ^= h2;
+	BOOST_CHECK(h1 == FixedHash<2>("0x1111"));
+}
+
+BOOST_AUTO_TEST_CASE(FixedHashOR)
+{
+	FixedHash<4> h1("0xD3ADB33F");
+	FixedHash<4> h2("0xBAADF00D");
+	FixedHash<4> res("0xFBADF33F");
+
+	BOOST_CHECK((h1 | h2) == res);
+	h1 |= h2;
+	BOOST_CHECK(h1 == res);
+}
+
+BOOST_AUTO_TEST_CASE(FixedHashAND)
+{
+	FixedHash<4> h1("0xD3ADB33F");
+	FixedHash<4> h2("0xBAADF00D");
+	FixedHash<4> h3("0x92aDB00D");
+
+	BOOST_CHECK((h1 & h2) == h3);
+	h1 &= h2;
+	BOOST_CHECK(h1 = h3);
+}
+
+BOOST_AUTO_TEST_CASE(FixedHashInvert)
+{
+	FixedHash<4> h1("0xD3ADB33F");
+	FixedHash<4> h2("0x2C524CC0");
+
+	BOOST_CHECK(~h1  == h2);
+}
+
+BOOST_AUTO_TEST_CASE(FixedHashContains)
+{
+	FixedHash<4> h1("0xD3ADB331");
+	FixedHash<4> h2("0x0000B331");
+	FixedHash<4> h3("0x0000000C");
+
+	BOOST_CHECK(h1.contains(h2));
+	BOOST_CHECK(!h1.contains(h3));
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}