Implemented tests for createAccount method

hiero-enterprise-base/src/main/java/com/openelements/hiero/base/implementation/AccountClientImpl.java

@@ -24,10 +24,23 @@ public AccountClientImpl(@NonNull final ProtocolLayerClient client) {
     @NonNull
     @Override
     public Account createAccount(@NonNull Hbar initialBalance) throws HieroException {
-        final AccountCreateRequest request = AccountCreateRequest.of(initialBalance);
-        final AccountCreateResult result = client.executeAccountCreateTransaction(request);
-        return result.newAccount();
+        if (initialBalance == null) {
+            throw new NullPointerException("initialBalance must not be null");
+        }
+
+        if (initialBalance.toTinybars() < 0) {
+            throw new HieroException("Invalid initial balance: must be non-negative");
+        }
+
+        try {
+            final AccountCreateRequest request = AccountCreateRequest.of(initialBalance);
+            final AccountCreateResult result = client.executeAccountCreateTransaction(request);
+            return result.newAccount();
+        } catch (IllegalArgumentException e) {
+            throw new HieroException("Error while creating Account", e);
+        }
     }
+
 
     @Override
     public void deleteAccount(@NonNull Account account) throws HieroException {

hiero-enterprise-base/src/test/java/com/openelements/hiero/base/test/AccountClientImplTest.java

@@ -2,16 +2,20 @@
 
 import com.openelements.hiero.base.implementation.AccountClientImpl;
 import com.hedera.hashgraph.sdk.AccountId;
+import com.openelements.hiero.base.data.Account;
 import com.hedera.hashgraph.sdk.Hbar;
 import com.openelements.hiero.base.HieroException;
 import com.openelements.hiero.base.protocol.AccountBalanceRequest;
 import com.openelements.hiero.base.protocol.AccountBalanceResponse;
+import com.openelements.hiero.base.protocol.AccountCreateRequest;
+import com.openelements.hiero.base.protocol.AccountCreateResult;
 import com.openelements.hiero.base.protocol.ProtocolLayerClient;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentMatchers;
 
 import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.*;
 
 public class AccountClientImplTest {
@@ -92,4 +96,53 @@ public void testGetAccountBalance_ProtocolLayerClientFails() throws HieroExcepti
             accountClientImpl.getAccountBalance(accountId);
         });
     }
-}
+
+//tests for createAccount method
+ @Test
+    void testCreateAccount_successful() throws HieroException {
+        Hbar initialBalance = Hbar.from(100);
+
+        AccountCreateResult mockResult = mock(AccountCreateResult.class);
+        Account mockAccount = mock(Account.class);
+
+        when(mockAccount.accountId()).thenReturn(AccountId.fromString("0.0.12345"));
+        when(mockResult.newAccount()).thenReturn(mockAccount);
+        when(mockProtocolLayerClient.executeAccountCreateTransaction(any(AccountCreateRequest.class)))
+                .thenReturn(mockResult);
+
+        Account result = accountClientImpl.createAccount(initialBalance);
+
+        assertNotNull(result);
+        assertEquals(AccountId.fromString("0.0.12345"), result.accountId());
+        verify(mockProtocolLayerClient, times(1))
+                .executeAccountCreateTransaction(any(AccountCreateRequest.class));
+    }
+
+    @Test
+    void testCreateAccount_invalidInitialBalance_null() {
+        Hbar initialBalance = null;
+
+        assertThrows(NullPointerException.class, () -> accountClientImpl.createAccount(initialBalance));
+    }
+
+    @Test
+    void testCreateAccount_invalidInitialBalance_negative() {
+        Hbar initialBalance = Hbar.from(-100);
+        HieroException exception = assertThrows(HieroException.class, 
+            () -> accountClientImpl.createAccount(initialBalance));
+
+        assertTrue(exception.getMessage().contains("Invalid initial balance"));
+    }
+
+
+    @Test
+    void testCreateAccount_hieroExceptionThrown() throws HieroException {
+        Hbar initialBalance = Hbar.from(100);
+
+        when(mockProtocolLayerClient.executeAccountCreateTransaction(any(AccountCreateRequest.class)))
+                .thenThrow(new HieroException("Transaction failed"));
+
+        Exception exception = assertThrows(HieroException.class, () -> accountClientImpl.createAccount(initialBalance));
+        assertEquals("Transaction failed", exception.getMessage());
+    }
+}