diff --git a/graphenebase/aes.py b/graphenebase/aes.py
index cf02f7c3..7a7357e4 100644
--- a/graphenebase/aes.py
+++ b/graphenebase/aes.py
@@ -1,4 +1,4 @@
-try:
+try:   # pragma: no cover
     from Cryptodome.Cipher import AES
     from Cryptodome import Random
 except ImportError:   # pragma: no cover
diff --git a/graphenebase/base58.py b/graphenebase/base58.py
index efd3137d..2681deaa 100644
--- a/graphenebase/base58.py
+++ b/graphenebase/base58.py
@@ -1,8 +1,11 @@
-from binascii import hexlify, unhexlify
 import hashlib
-import sys
+# import sys
 import string
 import logging
+
+from binascii import hexlify, unhexlify
+from .utils import _bytes
+
 log = logging.getLogger(__name__)
 
 """ Default Prefix """
@@ -23,12 +26,13 @@ class Base58(object):
     """Base58 base class
 
     This class serves as an abstraction layer to deal with base58 encoded
-    strings and their corresponding hex and binary representation throughout the
-    library.
+    strings and their corresponding hex and binary representation throughout
+    the library.
 
     :param data: Data to initialize object, e.g. pubkey data, address data, ...
     :type data: hex, wif, bip38 encrypted wif, base58 string
-    :param str prefix: Prefix to use for Address/PubKey strings (defaults to ``GPH``)
+    :param str prefix: Prefix to use for Address/PubKey strings (defaults to
+        ``GPH``)
     :return: Base58 object initialized with ``data``
     :rtype: Base58
     :raises ValueError: if data cannot be decoded
@@ -36,7 +40,8 @@ class Base58(object):
     * ``bytes(Base58)``: Returns the raw data
     * ``str(Base58)``:   Returns the readable ``Base58CheckEncoded`` data.
     * ``repr(Base58)``:  Gives the hex representation of the data.
-    *  ``format(Base58,_format)`` Formats the instance according to ``_format``:
+    *  ``format(Base58,_format)`` Formats the instance according to
+        ``_format``:
         * ``"wif"``: prefixed with ``0x00``. Yields a valid wif key
         * ``"bts"``: prefixed with ``BTS``
         * etc.
@@ -50,7 +55,10 @@ def __init__(self, data, prefix=PREFIX):
             self._hex = data
         elif data[0] == "5" or data[0] == "6":
             self._hex = base58CheckDecode(data)
-        elif data[0] == "K" or data[0] == "L":
+        elif data[0] == "K" or data[0] == "L":  # pragma: no cover
+            raise NotImplementedError(
+                "Private Keys starting with L or K are not supported!"
+            )
             self._hex = base58CheckDecode(data)[:-2]
         elif data[:len(self._prefix)] == self._prefix:
             self._hex = gphBase58CheckDecode(data[len(self._prefix):])
@@ -74,7 +82,10 @@ def __format__(self, _format):
         elif _format.upper() in known_prefixes:
             return _format.upper() + str(self)
         else:
-            log.warn("Format %s unkown. You've been warned!\n" % _format)
+            log.warning(
+                "Format {} unkown. You've been warned!\n".format(
+                    _format
+                ))
             return _format.upper() + str(self)
 
     def __repr__(self):
@@ -108,10 +119,13 @@ def __bytes__(self):
 
 
 def base58decode(base58_str):
+    """
     if sys.version > '3':
         base58_text = bytes(base58_str, "ascii")
-    else:
+    else:  # pragma: no cover
         base58_text = base58_str.encode("ascii")
+    """
+    base58_text = _bytes(base58_str)
     n = 0
     leading_zeroes_count = 0
     for b in base58_text:
@@ -129,10 +143,13 @@ def base58decode(base58_str):
 
 
 def base58encode(hexstring):
+    """
     if sys.version > '3':
         byteseq = bytes(unhexlify(bytes(hexstring, 'ascii')))
     else:
         byteseq = bytearray(unhexlify(hexstring.decode("ascii")))
+    """
+    byteseq = unhexlify(_bytes(hexstring))
     n = 0
     leading_zeroes_count = 0
     for c in byteseq:
diff --git a/graphenebase/bip38.py b/graphenebase/bip38.py
index 07ff31da..5453277a 100644
--- a/graphenebase/bip38.py
+++ b/graphenebase/bip38.py
@@ -1,9 +1,11 @@
-import sys
+# import sys
 import logging
 import hashlib
 from binascii import hexlify, unhexlify
 from .account import PrivateKey
 from .base58 import Base58, base58decode
+from .utils import _bytes
+
 log = logging.getLogger(__name__)
 
 try:
@@ -15,11 +17,11 @@
         raise ImportError("Missing dependency: pyCryptodome")
 
 SCRYPT_MODULE = None
-if not SCRYPT_MODULE:
+if not SCRYPT_MODULE:  # pragma: no branch
     try:
         import scrypt
         SCRYPT_MODULE = "scrypt"
-    except ImportError:   # pragma: no cover
+    except ImportError:
         try:
             import pylibscrypt as scrypt
             SCRYPT_MODULE = "pylibscrypt"
@@ -58,14 +60,17 @@ def encrypt(privkey, passphrase):
 
     privkeyhex = repr(privkey)   # hex
     addr = format(privkey.bitcoin.address, "BTC")
+    """
     if sys.version > '3':
         a = bytes(addr, 'ascii')
     else:
         a = bytes(addr).encode('ascii')
+    """
+    a = _bytes(addr)
     salt = hashlib.sha256(hashlib.sha256(a).digest()).digest()[0:4]
-    if SCRYPT_MODULE == "scrypt":
+    if SCRYPT_MODULE == "scrypt":  # pragma: no branch
         key = scrypt.hash(passphrase, salt, 16384, 8, 8)
-    elif SCRYPT_MODULE == "pylibscrypt":
+    elif SCRYPT_MODULE == "pylibscrypt":  # pragma: no branch
         key = scrypt.scrypt(bytes(passphrase, "utf-8"), salt, 16384, 8, 8)
     else:   # pragma: no cover
         raise ValueError("No scrypt module loaded")
@@ -101,9 +106,9 @@ def decrypt(encrypted_privkey, passphrase):
     assert flagbyte == b'\xc0', "Flagbyte has to be 0xc0"
     salt = d[0:4]
     d = d[4:-4]
-    if SCRYPT_MODULE == "scrypt":
+    if SCRYPT_MODULE == "scrypt":  # pragma: no branch
         key = scrypt.hash(passphrase, salt, 16384, 8, 8)
-    elif SCRYPT_MODULE == "pylibscrypt":
+    elif SCRYPT_MODULE == "pylibscrypt":  # pragma: no branch
         key = scrypt.scrypt(bytes(passphrase, "utf-8"), salt, 16384, 8, 8)
     else:
         raise ValueError("No scrypt module loaded")
@@ -121,10 +126,13 @@ def decrypt(encrypted_privkey, passphrase):
     """ Verify Salt """
     privkey = PrivateKey(format(wif, "wif"))
     addr = format(privkey.bitcoin.address, "BTC")
+    """
     if sys.version > '3':
         a = bytes(addr, 'ascii')
     else:
         a = bytes(addr).encode('ascii')
+    """
+    a = _bytes(addr)
     saltverify = hashlib.sha256(hashlib.sha256(a).digest()).digest()[0:4]
     if saltverify != salt:   # pragma: no cover
         raise SaltException(
diff --git a/graphenebase/ecdsa.py b/graphenebase/ecdsa.py
index e281054a..dc8ebc25 100644
--- a/graphenebase/ecdsa.py
+++ b/graphenebase/ecdsa.py
@@ -1,20 +1,23 @@
 from __future__ import absolute_import
 
-import sys
+# import sys
 import time
 import ecdsa
 import hashlib
-from binascii import hexlify
 import struct
 import logging
+
+from binascii import hexlify
+
 from .account import PrivateKey, PublicKey
+from .utils import _bytes
 log = logging.getLogger(__name__)
 
 SECP256K1_MODULE = None
 SECP256K1_AVAILABLE = False
 CRYPTOGRAPHY_AVAILABLE = False
 GMPY2_MODULE = False
-if not SECP256K1_MODULE:
+if not SECP256K1_MODULE:  # pragma: no branch
     try:
         import secp256k1
         SECP256K1_MODULE = "secp256k1"
@@ -27,7 +30,7 @@
         except ImportError:
             SECP256K1_MODULE = "ecdsa"
 
-    try:
+    try:  # pragma: no branch
         from cryptography.hazmat.backends import default_backend
         from cryptography.hazmat.primitives import hashes
         from cryptography.hazmat.primitives.asymmetric import ec
@@ -61,10 +64,13 @@ def compressedPubkey(pk):
         x = p.x()
         y = p.y()
     x_str = ecdsa.util.number_to_string(x, order)
+    """
     if sys.version > '3':
         return bytes(chr(2 + (y & 1)), 'ascii') + x_str
     else:
         return bytes(chr(2 + (y & 1))).encode("ascii") + x_str
+    """
+    return _bytes(chr(2 + (y & 1))) + x_str
 
 
 def recover_public_key(digest, signature, i, message=None):
@@ -100,9 +106,9 @@ def recover_public_key(digest, signature, i, message=None):
         return public_key
     else:
         # Not strictly necessary, but let's verify the message for paranoia's sake.
-        if not ecdsa.VerifyingKey.from_public_point(Q, curve=ecdsa.SECP256k1).verify_digest(signature, digest, sigdecode=ecdsa.util.sigdecode_string):
+        if not ecdsa.VerifyingKey.from_public_point(Q, curve=ecdsa.SECP256k1).verify_digest(signature, digest, sigdecode=ecdsa.util.sigdecode_string):   # pragma: no cover
             return None   # pragma: no cover
-        return ecdsa.VerifyingKey.from_public_point(Q, curve=ecdsa.SECP256k1)
+        return ecdsa.VerifyingKey.from_public_point(Q, curve=ecdsa.SECP256k1)   # pragma: no cover
 
 
 def recoverPubkeyParameter(message, digest, signature, pubkey):
@@ -127,14 +133,13 @@ def recoverPubkeyParameter(message, digest, signature, pubkey):
             p = recover_public_key(digest, signature, i)
             p_comp = hexlify(compressedPubkey(p))
             p_string = hexlify(p.to_string())
-            if isinstance(pubkey, PublicKey):
-                pubkey_string = bytes(repr(pubkey), 'latin')
-            else:
+            if isinstance(pubkey, PublicKey):  # pragma: no cover
+                pubkey_string = bytes(repr(pubkey), 'ascii')
+            else:  # pragma: no cover
                 pubkey_string = hexlify(pubkey.to_string())
             if (p_string == pubkey_string or
-                    p_comp == pubkey_string):
+                    p_comp == pubkey_string):  # pragma: no cover
                 return i
-    return None
 
 
 def sign_message(message, wif, hashfn=hashlib.sha256):
@@ -148,10 +153,13 @@ def sign_message(message, wif, hashfn=hashlib.sha256):
 
     digest = hashfn(message).digest()
     priv_key = PrivateKey(wif)
+    """
     if sys.version > '3':
         p = bytes(priv_key)
     else:
         p = bytes(priv_key.__bytes__())
+    """
+    p = bytes(priv_key)
 
     if SECP256K1_MODULE == "secp256k1":
         ndata = secp256k1.ffi.new("const int *ndata")
@@ -206,12 +214,12 @@ def sign_message(message, wif, hashfn=hashlib.sha256):
                 i += 4   # compressed
                 i += 27  # compact
                 break
-    else:
+    else:   # pragma: no branch
         cnt = 0
         sk = ecdsa.SigningKey.from_string(p, curve=ecdsa.SECP256k1)
         while 1:
             cnt += 1
-            if not cnt % 20:
+            if not cnt % 20:  # pragma: no branch
                 log.info("Still searching for a canonical signature. Tried %d times already!" % cnt)
 
             # Deterministic k
@@ -262,7 +270,7 @@ def sign_message(message, wif, hashfn=hashlib.sha256):
 def verify_message(message, signature, hashfn=hashlib.sha256):
     if not isinstance(message, bytes):
         message = bytes(message, "utf-8")
-    if not isinstance(signature, bytes):
+    if not isinstance(signature, bytes):  # pragma: no cover
         signature = bytes(signature, "utf-8")
     if not isinstance(message, bytes):
         raise AssertionError()
@@ -292,7 +300,7 @@ def verify_message(message, signature, hashfn=hashlib.sha256):
         sigder = encode_dss_signature(r, s)
         p.verify(sigder, message, ec.ECDSA(hashes.SHA256()))
         phex = compressedPubkey(p)
-    else:
+    else:  # pragma: no branch
         p = recover_public_key(digest, sig, recoverParameter)
         # Will throw an exception of not valid
         p.verify_digest(
@@ -308,10 +316,13 @@ def verify_message(message, signature, hashfn=hashlib.sha256):
 def pointToPubkey(x, y, order=None):
     order = order or ecdsa.SECP256k1.order
     x_str = ecdsa.util.number_to_string(x, order)
+    """
     if sys.version > '3':
         return bytes(chr(2 + (y & 1)), 'ascii') + x_str
     else:
         return bytes(chr(2 + (y & 1))).encode("ascii") + x_str
+    """
+    return _bytes(chr(2 + (y & 1))) + x_str   # pragma: no cover
 
 
 def tweakaddPubkey(pk, digest256, SECP256K1_MODULE=SECP256K1_MODULE):
diff --git a/setup.cfg b/setup.cfg
index b78d7ed4..f1315bf5 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -32,6 +32,7 @@ exclude_lines =
     if 0:
     if __name__ == .__main__.:
     if sys.version > '3': 
+    SECP256K1_MODULE
 
 [flake8]
 ignore = E501,F401
diff --git a/tests/test_account.py b/tests/test_account.py
index 6d95c4f5..dfaedc3d 100644
--- a/tests/test_account.py
+++ b/tests/test_account.py
@@ -1,4 +1,6 @@
+import ecdsa
 import unittest
+import hashlib
 from graphenebase.base58 import Base58
 from graphenebase.account import BrainKey, Address, PublicKey, PrivateKey, PasswordKey, GrapheneAddress, BitcoinAddress
 
@@ -242,14 +244,15 @@ def test_btcprivkeystr(self):
                           ])
 
     def test_gphprivkeystr(self):
-        self.assertEqual([str(Address.from_pubkey(PrivateKey("5HvVz6XMx84aC5KaaBbwYrRLvWE46cH6zVnv4827SBPLorg76oq").pubkey)),
-                          str(Address.from_pubkey(PrivateKey("5Jete5oFNjjk3aUMkKuxgAXsp7ZyhgJbYNiNjHLvq5xzXkiqw7R").pubkey)),
-                          str(Address.from_pubkey(PrivateKey("5KDT58ksNsVKjYShG4Ls5ZtredybSxzmKec8juj7CojZj6LPRF7").pubkey, compressed=False, prefix="BTS")),
-                          ], [
-                            'GPHBXqRucGm7nRkk6jm7BNspTJTWRtNcx7k5',
-                            'GPH5tTDDR6M3mkcyVv16edsw8dGUyNQZrvKU',
-                            'BTS4XPkBqYw882fH5aR5S8mMKXCaZ1yVA76f'
-                          ])
+        self.assertEqual([
+            str(Address.from_pubkey(PrivateKey("5HvVz6XMx84aC5KaaBbwYrRLvWE46cH6zVnv4827SBPLorg76oq").pubkey)),
+            str(Address.from_pubkey(PrivateKey("5Jete5oFNjjk3aUMkKuxgAXsp7ZyhgJbYNiNjHLvq5xzXkiqw7R").pubkey)),
+            str(Address.from_pubkey(PrivateKey("5KDT58ksNsVKjYShG4Ls5ZtredybSxzmKec8juj7CojZj6LPRF7").pubkey, compressed=False, prefix="BTS")),
+        ], [
+            'GPHBXqRucGm7nRkk6jm7BNspTJTWRtNcx7k5',
+            'GPH5tTDDR6M3mkcyVv16edsw8dGUyNQZrvKU',
+            'BTS4XPkBqYw882fH5aR5S8mMKXCaZ1yVA76f'
+        ])
 
     def test_password_suggest(self):
         self.assertEqual(
@@ -262,6 +265,26 @@ def test_child(self):
         self.assertIsInstance(p2, PrivateKey)
         self.assertEqual(str(p2), "5JQ6AQmjpbEZjJBLnoa3BaWa9y3LDTUBeSDwEGQD2UjYkb1gY2x")
 
+    def test_child_pub(self):
+        p = PrivateKey("5JWcdkhL3w4RkVPcZMdJsjos22yB5cSkPExerktvKnRNZR5gx1S")
+        pub = p.pubkey
+        point = pub.point()
+        self.assertEqual([
+            ecdsa.util.number_to_string(point.x(), ecdsa.SECP256k1.order),
+            ecdsa.util.number_to_string(point.y(), ecdsa.SECP256k1.order)
+        ], [
+            b"\x90d5\xf6\xf9\xceo=NL\xf8\xd3\xd0\xdd\xce \x9a\x83'w8\xff\xdc~\xaec\x08\xf4\xed)c\xdf",
+            b'\r\xa8tl\xf1:a\x89\xa2\x81\x96\\X\x0fBA]\x86\xe9l#*\x89%\xea\x152T\xbb\x87\x9f`'
+        ])
+        self.assertEqual(
+            repr(pub.child(b"foobar")),
+            "022a42ae1e9af8f84544c9a1970308c31f864dfb4f5998c45ef76e11d307cc77d5"
+        )
+        self.assertEqual(
+            repr(pub.add(hashlib.sha256(b"Foobar").digest())),
+            "0354a2c06c398990c52933df0c93b9904a4b23b0e2d524a3b0075c72adaa4e459e"
+        )
+
     def test_BrainKey_sequence(self):
         b = BrainKey("COLORER BICORN KASBEKE FAERIE LOCHIA GOMUTI SOVKHOZ Y GERMAL AUNTIE PERFUMY TIME FEATURE GANGAN CELEMIN MATZO")
         self.assertEqual(str(next(b).get_private_key()), "5Hsbn6kXio4bb7eW5bX7kTp2sdkmbzP8kGWoau46Cf7en7T1RRE")
@@ -275,3 +298,17 @@ def test_new_BrainKey(self):
         w = BrainKey().get_private_key()
         self.assertIsInstance(w, PrivateKey)
         self.assertEqual(str(w)[0], "5")  # is a wif key that starts with 5
+
+    def test_derive_private_key(self):
+        p = PrivateKey("5JWcdkhL3w4RkVPcZMdJsjos22yB5cSkPExerktvKnRNZR5gx1S")
+        p2 = p.derive_private_key(10)
+        self.assertEqual(
+            repr(p2),
+            "2dc7cb99933132e25b37710f9ea806228b04a583da11a137ef97fd42c0007390"
+        )
+
+    def test_init_wrong_format(self):
+        with self.assertRaises(NotImplementedError):
+            PrivateKey("KJWcdkhL3w4RkVPcZMdJsjos22yB5cSkPExerktvKnRNZR5gx1S")
+        with self.assertRaises(NotImplementedError):
+            PrivateKey("LJWcdkhL3w4RkVPcZMdJsjos22yB5cSkPExerktvKnRNZR5gx1S")
diff --git a/tests/test_api.py b/tests/test_api.py
new file mode 100644
index 00000000..1294b1e5
--- /dev/null
+++ b/tests/test_api.py
@@ -0,0 +1,72 @@
+import unittest
+from grapheneapi.api import Api, Websocket, Http
+from grapheneapi import exceptions
+
+urls = [
+    "wss://node.bitshares.eu",
+    "https://eu.nodes.bitshares.ws"
+]
+
+
+class Testcases(unittest.TestCase):
+
+    def test_apiInit(self):
+        api = Api(urls)
+        self.assertEqual(len(api._url_counter), 2)
+        api_single = Api(urls[0])
+        self.assertEqual(len(api_single._url_counter), 1)
+
+    def test_chain_params(self):
+        api = Api(urls)
+        p = api.chain_params
+        self.assertEqual(p, api.get_network())
+        self.assertEqual(p.get("chain_id"), "4018d7844c78f6a6c41c6a552b898022310fc5dec06da467ee7905a8dad512c8")
+
+    def test_websocket_connection(self):
+        api = Api(urls[0])
+        self.assertIsInstance(
+            api.connection,
+            Websocket
+        )
+        api = Api(urls[1])
+        self.assertIsInstance(
+            api.connection,
+            Http
+        )
+        with self.assertRaises(ValueError):
+            Api("hssp://error.example.com", num_retries=1)
+
+    def test_call(self):
+        api = Api(urls[0])
+        api.get_objects(["2.8.0"], api="database")
+
+    def test_cconnection_exceptions(self):
+        with self.assertRaises(exceptions.NumRetriesReached):
+            api = Api("http://error.example.com", num_retries=0)
+            api.get_objects(["2.8.0"])
+        with self.assertRaises(exceptions.NumRetriesReached):
+            api = Api("http://error.example.com", num_retries=1)
+            api.get_objects(["2.8.0"])
+
+    def test_raise_rpc_error_wss(self):
+        api = Api(urls[0], num_retries=-1)
+        with self.assertRaises(exceptions.RPCError):
+            api.get_SOMETHING(["2.8.0"])
+        api.connection.disconnect()
+        api.connection.disconnect()
+
+    def test_raise_rpc_error_https(self):
+        api = Api(urls[1], num_retries=-1)
+        with self.assertRaises(exceptions.RPCError):
+            api.get_SOMETHING(["2.8.0"])
+
+    def test_login(self):
+        Api(urls[0], "User", "password", num_retries=-1)
+        Api(urls[0], None, None, num_retries=-1)
+
+    def test_rollover(self):
+        api = Api([
+            "http://error.example.com",
+            "wss://node.bitshares.eu"
+        ])
+        api.get_objects(["2.8.0"])
diff --git a/tests/test_base58.py b/tests/test_base58.py
index c9a9666d..185b2991 100644
--- a/tests/test_base58.py
+++ b/tests/test_base58.py
@@ -119,6 +119,27 @@ def test_Base58(self):
                           "5Jete5oFNjjk3aUMkKuxgAXsp7ZyhgJbYNiNjHLvq5xzXkiqw7R",
                           "5KDT58ksNsVKjYShG4Ls5ZtredybSxzmKec8juj7CojZj6LPRF7"])
 
+    def test_leading_zeros(self):
+        # Leading zeros become ones
+        for i in range(1, 10):
+            self.assertEqual(
+                base58encode('00' * i),
+                '1' * (i + 1)
+            )
+
+        # Leading zeros become ones
+        self.assertEqual([
+            base58decode(base58encode('00')),
+            base58decode(base58encode('0000')),
+            base58decode(base58encode('000000')),
+            base58decode(base58encode('00000000')),
+        ], [
+            '000000',
+            '00000000',
+            '0000000000',
+            '000000000000'
+        ])
+
 
 if __name__ == '__main__':
     unittest.main()