diff --git a/.github/workflows/sonar-analysis.yml b/.github/workflows/sonar-analysis.yml
index 6e0dc40..8917b1c 100644
--- a/.github/workflows/sonar-analysis.yml
+++ b/.github/workflows/sonar-analysis.yml
@@ -36,6 +36,9 @@ jobs:
       - name: Check and Install Playwright
         run: yarn playwright install
 
+      - name: Unit test run
+        run: yarn test:coverage
+
       # Analyze with SonarCloud
       - name: Analyze with SonarCloud
         uses: SonarSource/sonarqube-scan-action@v5.0.0
diff --git a/src/email-crypto/pwdProtectedEmail.ts b/src/email-crypto/pwdProtectedEmail.ts
index ef2d3df..2f3ad64 100644
--- a/src/email-crypto/pwdProtectedEmail.ts
+++ b/src/email-crypto/pwdProtectedEmail.ts
@@ -48,11 +48,13 @@ export async function decryptPwdProtectedEmail(
   password: string,
   aux?: Uint8Array,
 ): Promise<Email> {
+  if (!encryptedEmail?.encEmail || !encryptedEmail?.encryptedKey) {
+    throw new InvalidInputEmail();
+  }
   try {
     const encryptionKey = await removePasswordProtection(encryptedEmail.encryptedKey, password);
     return await decryptEmail(encryptedEmail.encEmail, encryptionKey, aux);
   } catch (error) {
-    if (error instanceof InvalidInputEmail) throw error;
     if (error instanceof EmailPasswordOpenError) throw error;
     if (error instanceof EmailSymmetricDecryptionError) throw error;
     throw new FailedToDecryptEmail(error instanceof Error ? error.message : String(error));
diff --git a/src/email-crypto/pwdProtectedEmailAndSubject.ts b/src/email-crypto/pwdProtectedEmailAndSubject.ts
index 2bdf596..6cc5c63 100644
--- a/src/email-crypto/pwdProtectedEmailAndSubject.ts
+++ b/src/email-crypto/pwdProtectedEmailAndSubject.ts
@@ -50,11 +50,13 @@ export async function decryptPwdProtectedEmailAndSubject(
   password: string,
   aux?: Uint8Array,
 ): Promise<EmailAndSubject> {
+  if (!encryptedEmail?.encEmail || !encryptedEmail?.encryptedKey) {
+    throw new InvalidInputEmail();
+  }
   try {
     const encryptionKey = await removePasswordProtection(encryptedEmail.encryptedKey, password);
     return await decryptEmailAndSubject(encryptedEmail.encEmail, encryptionKey, aux);
   } catch (error) {
-    if (error instanceof InvalidInputEmail) throw error;
     if (error instanceof EmailPasswordOpenError) throw error;
     if (error instanceof EmailSymmetricDecryptionError) throw error;
     throw new FailedToDecryptEmail(error instanceof Error ? error.message : String(error));
diff --git a/tests/email-crypto/pwdProtectedEmail.test.ts b/tests/email-crypto/pwdProtectedEmail.test.ts
index dadb3c4..ffadeeb 100644
--- a/tests/email-crypto/pwdProtectedEmail.test.ts
+++ b/tests/email-crypto/pwdProtectedEmail.test.ts
@@ -8,7 +8,7 @@ import {
   EmailSymmetricDecryptionError,
   InvalidInputEmail,
 } from '../../src/email-crypto';
-import { Email, EmailAndSubject } from '../../src/types';
+import { Email, EmailAndSubject, PwdProtectedEmail, PwdProtectedEmailAndSubject } from '../../src/types';
 
 describe('Test email crypto functions', () => {
   const email: Email = {
@@ -52,9 +52,15 @@ describe('Test email crypto functions', () => {
     );
   });
 
+  it('should throw an error if input is invalid', async () => {
+    await expect(decryptPwdProtectedEmail({} as PwdProtectedEmail, sharedSecret)).rejects.toThrow(InvalidInputEmail);
+    await expect(decryptPwdProtectedEmailAndSubject({} as PwdProtectedEmailAndSubject, sharedSecret)).rejects.toThrow(
+      InvalidInputEmail,
+    );
+  });
+
   it('should throw an error if password-protected email is modified', async () => {
     const encryptedEmail = await createPwdProtectedEmail(email, sharedSecret);
-
     const modifiedCiphertext = encryptedEmail;
     modifiedCiphertext.encEmail.encText += 'modified ciphertext';
     await expect(decryptPwdProtectedEmail(modifiedCiphertext, sharedSecret)).rejects.toThrow(
diff --git a/tests/email-crypto/pwdProtectedEmailCoreErrors.test.ts b/tests/email-crypto/pwdProtectedEmailCoreErrors.test.ts
index 792eb7e..b00e558 100644
--- a/tests/email-crypto/pwdProtectedEmailCoreErrors.test.ts
+++ b/tests/email-crypto/pwdProtectedEmailCoreErrors.test.ts
@@ -49,10 +49,27 @@ describe('Test email crypto functions', () => {
     );
   });
 
-  it('throws FailedToDecryptEmail when decryption fails', async () => {
-    const encryptedEmail = {} as PwdProtectedEmail;
-    const encryptedEmailAndSubject = {} as PwdProtectedEmailAndSubject;
+  const encryptedEmail = {
+    encEmail: {
+      encText: 'Np2hSuNJinD6Z3KIiWhnH1qWBpaCed6dU2Du0JiDRxPLCJhMQ4FmQmqr5PRz3iHMWa7xWRRmsyeMyd1k8cwX4YRmVg==',
+    },
+    encryptedKey: {
+      encryptedKey: 'PTSrN0aCrMoQIeSxQmmCHBhPFnJw8hx+Xu4nnbW81I+dvbyGAZmEvQ==',
+      salt: 'JUh7Xi0arXw/bhF4d+IEAw==',
+    },
+  } as PwdProtectedEmail;
+  const encryptedEmailAndSubject = {
+    encEmail: {
+      encSubject: '6LD/Cnv8/mCDSns53eZzPRyNa3d9gk+gdkiFhzIGouxlQMBeE6YkOA==',
+      encText: 'nH1NJoZnO1Trv7RQ4+3Z+/epqt422zjJIBPO6nzSFq2pDlLvgOUcrqMlCicn+fK74XP7gYeKfd6z1Qa517XyPsCvdQ==',
+    },
+    encryptedKey: {
+      encryptedKey: 'ctMRiLHe5a3AxVIC8QdFOS7VXdVMrZOZsYuC5MUQ7jbzxQio75NN2g==',
+      salt: 'qWsXcWQlc/uo46b0c+if0A==',
+    },
+  } as PwdProtectedEmailAndSubject;
 
+  it('throws FailedToDecryptEmail when decryption fails', async () => {
     const spy = vi.spyOn(core, 'removePasswordProtection');
 
     spy.mockRejectedValue(new Error('removePasswordProtection: unexpected failure'));
@@ -63,4 +80,28 @@ describe('Test email crypto functions', () => {
       FailedToDecryptEmail,
     );
   });
+
+  it('throws FailedToDecryptEmail when decryption fails with string error', async () => {
+    const spy = vi.spyOn(core, 'removePasswordProtection');
+
+    spy.mockRejectedValue('removePasswordProtection: unexpected failure');
+
+    await expect(decryptPwdProtectedEmail(encryptedEmail, sharedSecret)).rejects.toBeInstanceOf(FailedToDecryptEmail);
+
+    await expect(decryptPwdProtectedEmailAndSubject(encryptedEmailAndSubject, sharedSecret)).rejects.toBeInstanceOf(
+      FailedToDecryptEmail,
+    );
+  });
+
+  it('throws FailedToEncryptEmail when encryption fails with string error', async () => {
+    const spy = vi.spyOn(core, 'passwordProtectKey');
+
+    spy.mockRejectedValue('passwordProtectKey: unexpected failure');
+
+    await expect(createPwdProtectedEmail(email, sharedSecret)).rejects.toBeInstanceOf(FailedToEncryptEmail);
+
+    await expect(createPwdProtectedEmailAndSubject(emailAndSubject, sharedSecret)).rejects.toBeInstanceOf(
+      FailedToEncryptEmail,
+    );
+  });
 });