diff --git a/letsencrypt/client/tests/crypto_util_test.py b/letsencrypt/client/tests/crypto_util_test.py
index 76cbc8310..272555d80 100644
--- a/letsencrypt/client/tests/crypto_util_test.py
+++ b/letsencrypt/client/tests/crypto_util_test.py
@@ -175,5 +175,16 @@ class GetCertInfoTest(unittest.TestCase):
         self._call('cert-san.pem')
 
 
+class B64CertToPEMTest(unittest.TestCase):
+    """Tests for letsencrypt.client.crypto_util.b64_cert_to_pem."""
+
+    def test_it(self):
+        from letsencrypt.client.crypto_util import b64_cert_to_pem
+        self.assertEqual(
+            b64_cert_to_pem(pkg_resources.resource_string(
+                __name__, 'testdata/cert.b64jose')),
+            pkg_resources.resource_string(__name__, 'testdata/cert.pem'))
+
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/letsencrypt/client/tests/testdata/cert.b64jose b/letsencrypt/client/tests/testdata/cert.b64jose
new file mode 100644
index 000000000..fa1abdb9f
--- /dev/null
+++ b/letsencrypt/client/tests/testdata/cert.b64jose
@@ -0,0 +1 @@
+MIIB3jCCAYigAwIBAgICBTkwDQYJKoZIhvcNAQELBQAwdzELMAkGA1UEBhMCVVMxETAPBgNVBAgMCE1pY2hpZ2FuMRIwEAYDVQQHDAlBbm4gQXJib3IxKzApBgNVBAoMIlVuaXZlcnNpdHkgb2YgTWljaGlnYW4gYW5kIHRoZSBFRkYxFDASBgNVBAMMC2V4YW1wbGUuY29tMB4XDTE0MTIxMTIyMzQ0NVoXDTE0MTIxODIyMzQ0NVowdzELMAkGA1UEBhMCVVMxETAPBgNVBAgMCE1pY2hpZ2FuMRIwEAYDVQQHDAlBbm4gQXJib3IxKzApBgNVBAoMIlVuaXZlcnNpdHkgb2YgTWljaGlnYW4gYW5kIHRoZSBFRkYxFDASBgNVBAMMC2V4YW1wbGUuY29tMFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAKx1c7RR7R_drnBSQ_zfx1vQLHUbFLh1AQQQ5R8DZUXd36efNK79vukFhN9HFoHZiUvOjm0c-pVE6K-EdE_twuUCAwEAATANBgkqhkiG9w0BAQsFAANBAC24z0IdwIVKSlntksllvr6zJepBH5fMndfk3XJp10jT6VE-14KNtjh02a56GoraAvJAT5_H67E8GvJ_ocNnB_o
\ No newline at end of file