diff --git a/tests/unit/test_chain_solana.py b/tests/unit/test_chain_solana.py
index 0fbd717e..fc265a8e 100644
--- a/tests/unit/test_chain_solana.py
+++ b/tests/unit/test_chain_solana.py
@@ -2,11 +2,13 @@
 from dataclasses import asdict, dataclass
 from pathlib import Path
 from tempfile import NamedTemporaryFile
+from typing import Any, Dict, List, Union
 
 import base58
 import pytest
 from nacl.signing import VerifyKey
 
+# Assuming these modules are part of the Aleph SDK
 from aleph.sdk.chains.common import get_verification_buffer
 from aleph.sdk.chains.solana import (
     SOLAccount,
@@ -19,72 +21,113 @@
 
 @dataclass
 class Message:
+    """A minimal message structure used for signing and verification tests."""
     chain: str
     sender: str
     type: str
     item_hash: str
 
 
-def test_get_fallback_account():
+def test_get_fallback_account() -> None:
+    """
+    Tests the creation of a SOLAccount instance using the fallback mechanism,
+    which typically generates a new keypair and saves it to a temporary file.
+    """
     with NamedTemporaryFile() as private_key_file:
         account: SOLAccount = get_fallback_account(path=Path(private_key_file.name))
 
+        # Assert fundamental characteristics of the generated account
         assert account.CHAIN == "SOL"
         assert account.CURVE == "curve25519"
+        # Check if the signing key has a verification key (i.e., it's a valid keypair)
         assert account._signing_key.verify_key
         assert isinstance(account.private_key, bytes)
+        # Check that the raw private key (seed) is 32 bytes long
         assert len(account.private_key) == 32
 
 
 @pytest.mark.asyncio
-async def test_SOLAccount(solana_account):
-    message = asdict(
+async def test_SOLAccount(solana_account: SOLAccount) -> None:
+    """
+    Tests the signing capability of a SOLAccount and verifies the signature
+    using raw cryptography tools (PyNaCl).
+    """
+    # 1. Arrange: Prepare message and signature process
+    message: Dict[str, Any] = asdict(
         Message("SOL", solana_account.get_address(), "SomeType", "ItemHash")
     )
     initial_message = message.copy()
+
+    # 2. Act: Sign the message (modifies the message dict in place)
     await solana_account.sign_message(message)
-    assert message["signature"]
+    assert "signature" in message
 
-    address = message["sender"]
-    assert address
+    # 3. Assert & Verification Checks
+    address: str = message["sender"]
     assert isinstance(address, str)
-    # assert len(address) == 44  # can also be 43?
-    signature = json.loads(message["signature"])
-
-    pubkey = base58.b58decode(signature["publicKey"])
-    assert isinstance(pubkey, bytes)
-    assert len(pubkey) == 32
 
-    verify_key = VerifyKey(pubkey)
-    verification_buffer = get_verification_buffer(message)
+    # Parse the signature object which is stored as a JSON string in the message
+    signature_obj: Dict[str, str] = json.loads(message["signature"])
+
+    # Extract the public key from the signature object
+    pubkey_base58: str = signature_obj["publicKey"]
+    pubkey_bytes: bytes = base58.b58decode(pubkey_base58)
+    assert isinstance(pubkey_bytes, bytes)
+    assert len(pubkey_bytes) == 32
+
+    # Instantiate the verification key using raw PyNaCl/nacl
+    verify_key = VerifyKey(pubkey_bytes)
+    
+    # Get the canonical buffer that was signed
+    verification_buffer: bytes = get_verification_buffer(message)
+    # Ensure the verification buffer is based on the unsigned content
     assert get_verification_buffer(initial_message) == verification_buffer
-    verif = verify_key.verify(
-        verification_buffer, signature=base58.b58decode(signature["signature"])
+
+    # Verify the signature against the buffer
+    verified_buffer = verify_key.verify(
+        verification_buffer, signature=base58.b58decode(signature_obj["signature"])
     )
 
-    assert verif == verification_buffer
-    assert message["sender"] == signature["publicKey"]
+    # If verification is successful, the returned value is the buffer itself
+    assert verified_buffer == verification_buffer
+    
+    # Sanity check: the sender address in the message must match the public key in the signature
+    assert message["sender"] == signature_obj["publicKey"]
 
-    pubkey = solana_account.get_public_key()
-    assert isinstance(pubkey, str)
-    assert len(pubkey) == 64
+    # Check the format of the key returned by the account object (assumed to be hex)
+    pubkey_hex: str = solana_account.get_public_key()
+    assert isinstance(pubkey_hex, str)
+    # A 32-byte key is 64 characters in hexadecimal format
+    assert len(pubkey_hex) == 64
 
 
 @pytest.mark.asyncio
-async def test_decrypt_curve25516(solana_account):
+async def test_decrypt_curve25516(solana_account: SOLAccount) -> None:
+    """
+    Tests the encryption and decryption loop using the Ed25519/curve25519 properties.
+    """
     assert solana_account.CURVE == "curve25519"
     content = b"SomeContent"
 
-    encrypted = await solana_account.encrypt(content)
+    # Encrypt
+    encrypted: bytes = await solana_account.encrypt(content)
     assert isinstance(encrypted, bytes)
-    decrypted = await solana_account.decrypt(encrypted)
+    
+    # Decrypt
+    decrypted: bytes = await solana_account.decrypt(encrypted)
     assert isinstance(decrypted, bytes)
+    
+    # Assert original content matches decrypted content
     assert content == decrypted
 
 
 @pytest.mark.asyncio
-async def test_verify_signature(solana_account):
-    message = asdict(
+async def test_verify_signature(solana_account: SOLAccount) -> None:
+    """
+    Tests the utility verification function with both string (Base58) and raw byte inputs.
+    """
+    # 1. Arrange: Sign the message
+    message: Dict[str, Any] = asdict(
         Message(
             "SOL",
             solana_account.get_address(),
@@ -93,30 +136,48 @@ async def test_verify_signature(solana_account):
         )
     )
     await solana_account.sign_message(message)
-    assert message["signature"]
-    raw_signature = json.loads(message["signature"])["signature"]
-    assert isinstance(raw_signature, str)
-
-    verify_signature(raw_signature, message["sender"], get_verification_buffer(message))
-
-    # as bytes
+    assert "signature" in message
+    
+    raw_signature_b58: str = json.loads(message["signature"])["signature"]
+    assert isinstance(raw_signature_b58, str)
+    verification_buffer: bytes = get_verification_buffer(message)
+
+    # 2. Test 1: Verify using Base58 encoded string inputs (standard API usage)
+    verify_signature(raw_signature_b58, message["sender"], verification_buffer)
+
+    # 3. Test 2: Verify using raw bytes inputs (for stricter type checks)
+    # NOTE: The decode("utf-8") call from the original script is removed here,
+    # assuming the verification buffer must be passed as raw bytes.
     verify_signature(
-        base58.b58decode(raw_signature),
-        base58.b58decode(message["sender"]),
-        get_verification_buffer(message).decode("utf-8"),
+        base58.b58decode(raw_signature_b58),  # signature as bytes
+        base58.b58decode(message["sender"]),  # sender (public key) as bytes
+        verification_buffer,                  # verification buffer as bytes
     )
 
 
 @pytest.mark.asyncio
-async def test_verify_signature_with_processed_message(solana_account, json_messages):
-    message = json_messages[0]
-    signature = json.loads(message["signature"])["signature"]
+async def test_verify_signature_with_processed_message(solana_account: SOLAccount, json_messages: List[Dict[str, Any]]) -> None:
+    """
+    Tests signature verification using a pre-processed/fixture message structure.
+    """
+    # Select the first fixture message
+    message: Dict[str, Any] = json_messages[0]
+    
+    # Extract the Base58 signature string
+    signature: str = json.loads(message["signature"])["signature"]
+    
+    # Perform verification
     verify_signature(signature, message["sender"], get_verification_buffer(message))
 
 
 @pytest.mark.asyncio
-async def test_verify_signature_with_forged_signature(solana_account):
-    message = asdict(
+async def test_verify_signature_with_forged_signature(solana_account: SOLAccount) -> None:
+    """
+    Tests that the verification function raises BadSignatureError when provided
+    with a valid public key but a randomly forged 64-byte signature.
+    """
+    # 1. Arrange: Create and sign a valid message
+    message: Dict[str, Any] = asdict(
         Message(
             "SOL",
             solana_account.get_address(),
@@ -125,28 +186,40 @@ async def test_verify_signature_with_forged_signature(solana_account):
         )
     )
     await solana_account.sign_message(message)
-    assert message["signature"]
-    # create forged 64 bit signature from random bytes
-    forged = base58.b58encode(bytes(64)).decode("utf-8")
+    assert "signature" in message
+    
+    # 2. Act: Create a forged signature
+    # Solana signatures are 64 bytes. Create a base58 string from 64 null bytes.
+    forged: str = base58.b58encode(bytes(64)).decode("utf-8")
 
+    # 3. Assert: Verification must fail
     with pytest.raises(BadSignatureError):
         verify_signature(forged, message["sender"], get_verification_buffer(message))
 
 
 @pytest.mark.asyncio
-async def test_sign_raw(solana_account):
-    buffer = b"SomeBuffer"
-    signature = await solana_account.sign_raw(buffer)
-    assert signature
+async def test_sign_raw(solana_account: SOLAccount) -> None:
+    """
+    Tests the sign_raw utility for signing an arbitrary byte buffer.
+    """
+    # 1. Arrange: Arbitrary buffer
+    buffer = b"SomeBufferToSign"
+    
+    # 2. Act: Sign the raw buffer
+    signature: bytes = await solana_account.sign_raw(buffer)
     assert isinstance(signature, bytes)
-
+    
+    # 3. Assert: Verify the raw signature using the account's address (public key)
     verify_signature(signature, solana_account.get_address(), buffer)
 
 
-def test_parse_solana_private_key_bytes():
+def test_parse_solana_private_key_bytes() -> None:
+    """
+    Tests parsing a 32-byte raw private key (seed).
+    """
     # Valid 32-byte private key
     private_key_bytes = bytes(range(32))
-    parsed_key = parse_private_key(private_key_bytes)
+    parsed_key: bytes = parse_private_key(private_key_bytes)
     assert isinstance(parsed_key, bytes)
     assert len(parsed_key) == 32
     assert parsed_key == private_key_bytes
@@ -158,36 +231,47 @@ def test_parse_solana_private_key_bytes():
         parse_private_key(bytes(range(31)))
 
 
-def test_parse_solana_private_key_base58():
-    # Valid base58 private key (32 bytes)
-    base58_key = base58.b58encode(bytes(range(32))).decode("utf-8")
-    parsed_key = parse_private_key(base58_key)
+def test_parse_solana_private_key_base58() -> None:
+    """
+    Tests parsing a private key encoded in Base58 (either 32-byte seed or 64-byte keypair).
+    """
+    # Valid 32-byte seed encoded in Base58
+    seed_bytes = bytes(range(32))
+    base58_key: str = base58.b58encode(seed_bytes).decode("utf-8")
+    parsed_key: bytes = parse_private_key(base58_key)
     assert isinstance(parsed_key, bytes)
     assert len(parsed_key) == 32
+    assert parsed_key == seed_bytes
 
     # Invalid base58 key (not decodable)
     with pytest.raises(ValueError, match="Invalid base58 encoded private key"):
         parse_private_key("invalid_base58_key")
 
-    # Invalid base58 key (wrong length)
+    # Invalid base58 key (wrong length after decoding)
     with pytest.raises(
         ValueError,
         match="The base58 decoded private key must be either 32 or 64 bytes long.",
     ):
+        # 31 bytes -> invalid length
         parse_private_key(base58.b58encode(bytes(range(31))).decode("utf-8"))
 
 
-def test_parse_solana_private_key_list():
-    # Valid list of uint8 integers (64 elements, but we only take the first 32 for private key)
-    uint8_list = list(range(64))
-    parsed_key = parse_private_key(uint8_list)
+def test_parse_solana_private_key_list() -> None:
+    """
+    Tests parsing a private key supplied as a list of integers (Solana's JSON keypair format).
+    The function should extract only the first 32 bytes (the private key/seed).
+    """
+    # Valid list of uint8 integers (64 elements: 32 bytes private key + 32 bytes public key)
+    uint8_list: List[int] = list(range(64))
+    parsed_key: bytes = parse_private_key(uint8_list)
     assert isinstance(parsed_key, bytes)
     assert len(parsed_key) == 32
+    # Ensure only the first 32 elements are taken
     assert parsed_key == bytes(range(32))
 
     # Invalid list (contains non-integers)
     with pytest.raises(ValueError, match="Invalid uint8 array"):
-        parse_private_key([1, 2, "not an int", 4])  # type: ignore  # Ignore type check for string
+        parse_private_key([1, 2, "not an int", 4])  # type: ignore 
 
     # Invalid list (less than 32 elements)
     with pytest.raises(