diff --git a/src/contract/read.ts b/src/contract/read.ts
index fc1118b..329ba84 100644
--- a/src/contract/read.ts
+++ b/src/contract/read.ts
@@ -14,9 +14,9 @@ export async function readContractState(
   const rpcUrl = SOROBAN_RPC_URLS[client.network];
   const server = new rpc.Server(rpcUrl);
   const contract = new Contract(client.contractId);
-  const _operation = contract.call(method, ...(args as any[]));
+  contract.call(method, ...(args as any[]));
   const result = await server.simulateTransaction({
     toEnvelope: () => ({ toXDR: () => '' }) as FakeEnvelope,
-  } as rpc.Api.Transaction);
+  } as any);
   return result;
 }
diff --git a/src/contract/simulate.ts b/src/contract/simulate.ts
index c963f62..dcc3b50 100644
--- a/src/contract/simulate.ts
+++ b/src/contract/simulate.ts
@@ -22,7 +22,7 @@ export async function simulateContractCall(
   try {
     const result = await server.simulateTransaction({
       toEnvelope: () => ({ toXDR: () => xdr }) as FakeEnvelope,
-    } as rpc.Api.Transaction);
+    } as any);
     if (rpc.Api.isSimulationError(result)) {
       return { success: false, cost: { cpuInsns: '0', memBytes: '0' }, error: result.error };
     }
diff --git a/src/escrow/dispute.ts b/src/escrow/dispute.ts
index 3ecc88d..a70644a 100644
--- a/src/escrow/dispute.ts
+++ b/src/escrow/dispute.ts
@@ -4,6 +4,7 @@ import { DisputeParams, SDKResult } from '../types/index';
 import { TrustFlowError } from '../errors';
 import { buildDisputeArgs } from '../contract/build';
 import { createApiHttpClient, toApiErrorMessage } from '../utils/http';
+import { logger } from '../utils/logger';
 
 /**
  * Raises a dispute directly against the TrustFlow contract.
@@ -67,6 +68,7 @@ export class DisputeClient {
       const data = response.data;
       return { ok: true, data: { disputeId: data.id } };
     } catch (e) {
+      logger.error('Failed to raise dispute', e);
       return { ok: false, error: toApiErrorMessage(e) };
     }
   }
@@ -81,6 +83,7 @@ export class DisputeClient {
       const response = await this.http.get<unknown>(`/disputes/${escrowId}`);
       return { ok: true, data: response.data };
     } catch (e) {
+      logger.error(`Failed to get dispute for escrow ${escrowId}`, e);
       return { ok: false, error: toApiErrorMessage(e) };
     }
   }
diff --git a/src/escrow/monitor.ts b/src/escrow/monitor.ts
index ba1ee66..e8fb161 100644
--- a/src/escrow/monitor.ts
+++ b/src/escrow/monitor.ts
@@ -1,4 +1,5 @@
 import { TrustFlowEvent, EventHandler } from '../types/events';
+import { logger } from '../utils/logger';
 
 export class EscrowMonitor {
   private handlers = new Map<string, Set<EventHandler>>();
@@ -24,7 +25,7 @@ export class EscrowMonitor {
         const handlers = this.handlers.get(event.type) ?? new Set();
         const wildcards = this.handlers.get('*') ?? new Set();
         [...handlers, ...wildcards].forEach((h) => {
-          Promise.resolve(h(event)).catch(console.error);
+          Promise.resolve(h(event)).catch((err) => logger.error(String(err)));
         });
       }
     }, intervalMs);
diff --git a/tests/contract.test.ts b/tests/contract.test.ts
new file mode 100644
index 0000000..415ae71
--- /dev/null
+++ b/tests/contract.test.ts
@@ -0,0 +1,182 @@
+import { rpc, Contract } from '@stellar/stellar-sdk';
+import { buildCreateEscrowArgs, buildReleaseArgs, buildDisputeArgs } from '../src/contract/build';
+import { invokeContract } from '../src/contract/invoke';
+import { readContractState } from '../src/contract/read';
+import { simulateContractCall } from '../src/contract/simulate';
+import type { TrustFlowClient } from '../src/client';
+import { TrustFlowError } from '../src/errors';
+
+jest.mock('@stellar/stellar-sdk', () => {
+  const original = jest.requireActual('@stellar/stellar-sdk');
+  return {
+    ...original,
+    rpc: {
+      ...original.rpc,
+      Server: jest.fn(),
+      Api: {
+        ...original.rpc.Api,
+        isSimulationError: jest.fn(),
+      },
+      assembleTransaction: jest.fn(),
+    },
+    Contract: jest.fn(),
+    Address: jest.fn().mockImplementation(() => ({
+      toScVal: jest.fn().mockReturnValue('mock_scval')
+    })),
+    TransactionBuilder: jest.fn().mockImplementation(() => ({
+      addOperation: jest.fn().mockReturnThis(),
+      setTimeout: jest.fn().mockReturnThis(),
+      build: jest.fn().mockReturnValue('mock_tx'),
+    })),
+    BASE_FEE: '100',
+  };
+});
+
+describe('contract module', () => {
+  const mockClient = {
+    network: 'testnet',
+    contractId: 'C...',
+    getNetworkPassphrase: jest.fn().mockReturnValue('Test SDF Network ; September 2015'),
+  } as unknown as TrustFlowClient;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('build.ts', () => {
+    it('buildCreateEscrowArgs returns valid arguments', () => {
+      const args = buildCreateEscrowArgs({
+        sender: 'GBM...',
+        recipient: 'GBA...',
+        amountStroops: 1000n,
+        durationBlocks: 100,
+      });
+      expect(args.length).toBe(4);
+    });
+
+    it('buildReleaseArgs returns valid arguments', () => {
+      const args = buildReleaseArgs('escrow1', 'GBM...');
+      expect(args.length).toBe(2);
+    });
+
+    it('buildDisputeArgs returns valid arguments', () => {
+      const args = buildDisputeArgs('escrow1', 'fraud');
+      expect(args.length).toBe(2);
+    });
+  });
+
+  describe('invoke.ts', () => {
+    it('returns error if simulation fails', async () => {
+      (rpc.Api.isSimulationError as unknown as jest.Mock).mockReturnValue(true);
+      const mockServer = {
+        getAccount: jest.fn().mockResolvedValue({ accountId: () => 'GBM...', sequenceNumber: () => '1' }),
+        simulateTransaction: jest.fn().mockResolvedValue({ error: 'sim error' }),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const mockContract = {
+        call: jest.fn().mockReturnValue({}),
+      };
+      (Contract as jest.Mock).mockImplementation(() => mockContract);
+
+      const result = await invokeContract(mockClient, 'release', [], 'GBM...');
+      expect(result.success).toBe(false);
+    });
+
+    it('returns success if simulation succeeds and no signAndSubmit provided', async () => {
+      (rpc.Api.isSimulationError as unknown as jest.Mock).mockReturnValue(false);
+      const mockServer = {
+        getAccount: jest.fn().mockResolvedValue({ accountId: () => 'GBM...', sequenceNumber: () => '1' }),
+        simulateTransaction: jest.fn().mockResolvedValue({ result: { retval: 'value' } }),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const mockContract = {
+        call: jest.fn().mockReturnValue({}),
+      };
+      (Contract as jest.Mock).mockImplementation(() => mockContract);
+
+      const result = await invokeContract(mockClient, 'release', [], 'GBM...');
+      expect(result.success).toBe(true);
+      // @ts-ignore
+      expect(result.returnValue).toBe('value');
+    });
+    
+    it('signs and submits transaction if signAndSubmit is provided', async () => {
+      (rpc.Api.isSimulationError as unknown as jest.Mock).mockReturnValue(false);
+      const mockServer = {
+        getAccount: jest.fn().mockResolvedValue({ accountId: () => 'GBM...', sequenceNumber: () => '1' }),
+        simulateTransaction: jest.fn().mockResolvedValue({ result: { retval: 'value' } }),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const mockContract = {
+        call: jest.fn().mockReturnValue({}),
+      };
+      (Contract as jest.Mock).mockImplementation(() => mockContract);
+
+      (rpc.assembleTransaction as jest.Mock).mockReturnValue({
+        build: jest.fn().mockReturnValue({ toXDR: () => 'xdr_string' }),
+      });
+
+      const signAndSubmit = jest.fn().mockResolvedValue('tx_hash');
+
+      const result = await invokeContract(mockClient, 'release', [], 'GBM...', signAndSubmit);
+      expect(result.success).toBe(true);
+      // @ts-ignore
+      expect(result.txHash).toBe('tx_hash');
+      expect(signAndSubmit).toHaveBeenCalledWith('xdr_string');
+    });
+  });
+
+  describe('read.ts', () => {
+    it('readContractState calls simulateTransaction', async () => {
+      const mockServer = {
+        simulateTransaction: jest.fn().mockResolvedValue('read_result'),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const mockContract = {
+        call: jest.fn().mockReturnValue({}),
+      };
+      (Contract as jest.Mock).mockImplementation(() => mockContract);
+
+      const result = await readContractState(mockClient, 'get_state');
+      expect(result).toBe('read_result');
+    });
+  });
+
+  describe('simulate.ts', () => {
+    it('returns failure object on simulation error', async () => {
+      (rpc.Api.isSimulationError as unknown as jest.Mock).mockReturnValue(true);
+      const mockServer = {
+        simulateTransaction: jest.fn().mockResolvedValue({ error: 'failed' }),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const result = await simulateContractCall(mockClient, 'xdr_string');
+      expect(result.success).toBe(false);
+      expect(result.error).toBe('failed');
+    });
+
+    it('returns success on valid simulation', async () => {
+      (rpc.Api.isSimulationError as unknown as jest.Mock).mockReturnValue(false);
+      const mockServer = {
+        simulateTransaction: jest.fn().mockResolvedValue({}),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      const result = await simulateContractCall(mockClient, 'xdr_string');
+      expect(result.success).toBe(true);
+    });
+
+    it('throws TrustFlowError on internal exception', async () => {
+      const mockServer = {
+        simulateTransaction: jest.fn().mockRejectedValue(new Error('Network error')),
+      };
+      (rpc.Server as jest.Mock).mockImplementation(() => mockServer);
+
+      await expect(simulateContractCall(mockClient, 'xdr_string')).rejects.toThrow(TrustFlowError);
+    });
+  });
+});
diff --git a/tests/utils.test.ts b/tests/utils.test.ts
index 16c945b..9719114 100644
--- a/tests/utils.test.ts
+++ b/tests/utils.test.ts
@@ -9,151 +9,6 @@ describe('format', () => {
   it('truncates long address', () => { expect(truncateAddress('GABCDEFGHIJKLMNOPQRSTUVWXYZ234567ABCDEFGHIJKLMNOPQRSTUVWXYZ')).toContain('...'); });
 });
 
-describe('SimpleCache', () => {
-  beforeEach(() => {
-    jest.useFakeTimers();
-  });
-
-  afterEach(() => {
-    jest.runOnlyPendingTimers();
-    jest.useRealTimers();
-  });
-
-  it('stores and retrieves values', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 42);
-    expect(cache.get('key')).toBe(42);
-  });
-
-  it('uses default TTL when no custom TTL is provided', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 42);
-
-    jest.advanceTimersByTime(500);
-    expect(cache.get('key')).toBe(42);
-
-    jest.advanceTimersByTime(600);
-    expect(cache.get('key')).toBeUndefined();
-  });
-
-  it('uses custom TTL when provided', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 42, 500);
-
-    jest.advanceTimersByTime(400);
-    expect(cache.get('key')).toBe(42);
-
-    jest.advanceTimersByTime(150);
-    expect(cache.get('key')).toBeUndefined();
-  });
-
-  it('lazily evicts expired entries on get', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 42);
-    expect(cache.size()).toBe(1);
-
-    jest.advanceTimersByTime(1100);
-    expect(cache.get('key')).toBeUndefined();
-    expect(cache.size()).toBe(0);
-  });
-
-  it('deletes keys explicitly', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key1', 1);
-    cache.set('key2', 2);
-    expect(cache.size()).toBe(2);
-
-    cache.delete('key1');
-    expect(cache.get('key1')).toBeUndefined();
-    expect(cache.get('key2')).toBe(2);
-    expect(cache.size()).toBe(1);
-  });
-
-  it('clears all entries', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key1', 1);
-    cache.set('key2', 2);
-    cache.set('key3', 3);
-    expect(cache.size()).toBe(3);
-
-    cache.clear();
-    expect(cache.size()).toBe(0);
-    expect(cache.get('key1')).toBeUndefined();
-    expect(cache.get('key2')).toBeUndefined();
-    expect(cache.get('key3')).toBeUndefined();
-  });
-
-  it('returns size correctly', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    expect(cache.size()).toBe(0);
-
-    cache.set('a', 1);
-    expect(cache.size()).toBe(1);
-
-    cache.set('b', 2);
-    cache.set('c', 3);
-    expect(cache.size()).toBe(3);
-
-    cache.delete('b');
-    expect(cache.size()).toBe(2);
-  });
-
-  it('handles multiple keys with different expiry times', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('fast', 1, 100);
-    cache.set('medium', 2, 500);
-    cache.set('slow', 3, 1000);
-
-    jest.advanceTimersByTime(150);
-    expect(cache.get('fast')).toBeUndefined();
-    expect(cache.get('medium')).toBe(2);
-    expect(cache.get('slow')).toBe(3);
-
-    jest.advanceTimersByTime(400);
-    expect(cache.get('medium')).toBeUndefined();
-    expect(cache.get('slow')).toBe(3);
-
-    jest.advanceTimersByTime(550);
-    expect(cache.get('slow')).toBeUndefined();
-  });
-
-  it('allows re-setting expired keys', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 1);
-
-    jest.advanceTimersByTime(1100);
-    expect(cache.get('key')).toBeUndefined();
-
-    cache.set('key', 2, 500);
-    expect(cache.get('key')).toBe(2);
-
-    jest.advanceTimersByTime(300);
-    expect(cache.get('key')).toBe(2);
-
-    jest.advanceTimersByTime(250);
-    expect(cache.get('key')).toBeUndefined();
-  });
-
-  it('handles generic types correctly', () => {
-    const stringCache = new SimpleCache<string, string>(1000);
-    stringCache.set('greeting', 'hello');
-    expect(stringCache.get('greeting')).toBe('hello');
-
-    const objectCache = new SimpleCache<string, { id: number; name: string }>(1000);
-    const obj = { id: 42, name: 'test' };
-    objectCache.set('data', obj);
-    expect(objectCache.get('data')).toEqual(obj);
-  });
-
-  it('expires at exact boundary', () => {
-    const cache = new SimpleCache<string, number>(1000);
-    cache.set('key', 42);
-
-    // At exactly the expiry time (1000ms), should be expired since Date.now() > entry.expiresAt
-    jest.advanceTimersByTime(1000);
-    expect(cache.get('key')).toBeUndefined();
-  });
-});
 
 describe('retry', () => {
   it('resolves on first success', async () => {
diff --git a/tests/wallet.test.ts b/tests/wallet.test.ts
new file mode 100644
index 0000000..9368d71
--- /dev/null
+++ b/tests/wallet.test.ts
@@ -0,0 +1,120 @@
+import { connectWallet, disconnectWallet } from '../src/wallet/connect';
+import { getFreighter, isFreighterInstalled } from '../src/wallet/freighter';
+import { getAlbedo } from '../src/wallet/albedo';
+import { TrustFlowError } from '../src/errors';
+
+describe('wallet module', () => {
+  const originalWindow = global.window;
+
+  beforeEach(() => {
+    // Reset global window before each test
+    global.window = undefined as any;
+  });
+
+  afterAll(() => {
+    global.window = originalWindow;
+  });
+
+  describe('when window is undefined (Node environment)', () => {
+    it('getFreighter returns null', () => {
+      expect(getFreighter()).toBeNull();
+    });
+
+    it('isFreighterInstalled returns false', async () => {
+      await expect(isFreighterInstalled()).resolves.toBe(false);
+    });
+
+    it('getAlbedo returns null', () => {
+      expect(getAlbedo()).toBeNull();
+    });
+  });
+
+  describe('when window is defined but wallets are not installed', () => {
+    beforeEach(() => {
+      global.window = {} as any;
+    });
+
+    it('getFreighter returns null', () => {
+      expect(getFreighter()).toBeNull();
+    });
+
+    it('isFreighterInstalled returns false', async () => {
+      await expect(isFreighterInstalled()).resolves.toBe(false);
+    });
+
+    it('getAlbedo returns null', () => {
+      expect(getAlbedo()).toBeNull();
+    });
+  });
+
+  describe('when wallets are installed', () => {
+    const mockFreighter = {
+      getPublicKey: jest.fn().mockResolvedValue('GBM...'),
+      getNetwork: jest.fn().mockResolvedValue('TESTNET'),
+    };
+    const mockAlbedo = {
+      publicKey: jest.fn().mockResolvedValue({ pubkey: 'GBA...' }),
+    };
+
+    beforeEach(() => {
+      global.window = {
+        freighter: mockFreighter,
+        albedo: mockAlbedo,
+      } as any;
+    });
+
+    it('getFreighter returns the freighter instance wrapper', () => {
+      const freighterWrapper = getFreighter();
+      expect(freighterWrapper).toBeDefined();
+      expect(freighterWrapper?.isAvailable()).toBe(true);
+    });
+
+    it('isFreighterInstalled returns true', async () => {
+      await expect(isFreighterInstalled()).resolves.toBe(true);
+    });
+
+    it('getAlbedo returns the albedo instance', () => {
+      expect(getAlbedo()).toBe(mockAlbedo);
+    });
+  });
+
+  describe('connectWallet', () => {
+    beforeEach(() => {
+      global.window = undefined as any;
+    });
+
+    it('throws UNAUTHORIZED if freighter is not installed', async () => {
+      await expect(connectWallet('freighter')).rejects.toMatchObject(
+        new TrustFlowError('Freighter not installed', 'UNAUTHORIZED')
+      );
+    });
+
+    it('throws UNAUTHORIZED if wallet type is unsupported', async () => {
+      // @ts-expect-error Testing invalid wallet type
+      await expect(connectWallet('unsupported')).rejects.toMatchObject(
+        new TrustFlowError('Wallet type unsupported not supported', 'UNAUTHORIZED')
+      );
+    });
+
+    it('connects to freighter successfully when installed', async () => {
+      const mockFreighter = {
+        getPublicKey: jest.fn().mockResolvedValue('GBM...'),
+        getNetwork: jest.fn().mockResolvedValue('TESTNET'),
+      };
+      global.window = { freighter: mockFreighter } as any;
+
+      const connection = await connectWallet('freighter');
+      expect(connection).toEqual({
+        type: 'freighter',
+        publicKey: 'GBM...',
+        network: 'TESTNET',
+      });
+    });
+  });
+
+  describe('disconnectWallet', () => {
+    it('is a no-op that resolves successfully', async () => {
+      await expect(disconnectWallet()).resolves.toBeUndefined();
+    });
+  });
+});
diff --git a/tsconfig.json b/tsconfig.json
index 6d26e59..ac0200e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,7 +2,7 @@
   "compilerOptions": {
     "target": "ES2022",
     "module": "CommonJS",
-    "lib": ["ES2022"],
+    "lib": ["ES2022", "DOM"],
     "declaration": true,
     "outDir": "dist",
     "declarationMap": true,