diff --git a/eip_96_blockhash_getter.se.py b/eip96/eip_96_blockhash_getter.se.py
similarity index 66%
rename from eip_96_blockhash_getter.se.py
rename to eip96/eip_96_blockhash_getter.se.py
index adf0e71..cd822d4 100644
--- a/eip_96_blockhash_getter.se.py
+++ b/eip96/eip_96_blockhash_getter.se.py
@@ -5,19 +5,21 @@ if msg.sender == 2**160 - 2:
         ~sstore(prev_block_number % 256, ~calldataload(0))
         # Use storage fields 256..511 to store the hashes of the last 256
         # blocks with block.number % 256 == 0
-        if not prev_block_number % 256:
+        if not (prev_block_number % 256):
             ~sstore(256 + (prev_block_number / 256) % 256, ~calldataload(0))
         # Use storage fields 512..767 to store the hashes of the last 256
         # blocks with block.number % 65536 == 0
-        if not prev_block_number % 65536:
+        if not (prev_block_number % 65536):
             ~sstore(512 + (prev_block_number / 65536) % 256, ~calldataload(0))
 # Getting the block hash
 else:
-    if block.number - ~calldataload(0) <= 256:
+    if ~calldataload(0) >= block.number:
+        return(0)
+    elif block.number - ~calldataload(0) <= 256:
         return(~sload(~calldataload(0) % 256))
-    elif not block.number % 256 and block.number - ~calldataload(0) <= 65536:
+    elif (not (~calldataload(0) % 256) and block.number - ~calldataload(0) <= 65536):
         return(~sload(256 + (~calldataload(0) / 256) % 256))
-    elif not block.number % 65536 and block.number - ~calldataload(0) <= 16777216:
+    elif (not (~calldataload(0) % 65536) and block.number - ~calldataload(0) <= 16777216):
         return(~sload(512 + (~calldataload(0) / 65536) % 256))
     else:
-        ~invalid()
+        return(~calldataload(0) % 256 == 0)
diff --git a/eip96/eip_96_test_script.py b/eip96/eip_96_test_script.py
new file mode 100644
index 0000000..bffa21b
--- /dev/null
+++ b/eip96/eip_96_test_script.py
@@ -0,0 +1,34 @@
+from ethereum import tester, vm
+from ethereum.utils import sha3, encode_int32, safe_ord, encode_hex
+from ethereum.state_transition import apply_message
+s = tester.state()
+c = s.contract('eip_96_blockhash_getter.se.py')
+blockhash_addr = b'\x00' * 19 + b'\x10'
+system_addr = b'\xff' * 19 + b'\xfe'
+s.state.set_code(blockhash_addr, s.state.get_code(c))
+
+def mk_hash_setting_message(data):
+    return vm.Message(sender=system_addr, to=blockhash_addr, value=0, gas=1000000, data=data)
+
+print("Setting block hashes")
+for i in range(1, 1000):
+    s.state.block_number = i + 1
+    o = apply_message(s.state, mk_hash_setting_message(sha3(str(i))))
+    if i % 100 == 0:
+        print("Set %d" % i)
+
+print("Testing reads")
+s.state.block_number = 1000
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(999)) == sha3(str(999))
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(998)) == sha3(str(998))
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(744)) == sha3(str(744))
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(743)) == b'\x00' * 32
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(1000)) == b'\x00' * 32
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(1001)) == b'\x00' * 32
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(513)) == b'\x00' * 32
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(512)) == sha3(str(512))
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(511)) == b'\x00' * 32
+assert s.send(tester.k0, blockhash_addr, 0, encode_int32(256)) == sha3(str(256))
+print("Tests passed!")
+
+print("EVM code: 0x%s" % encode_hex(s.state.get_code(blockhash_addr)))